OPINION

MEYER, Justice.

Dale Lee Underdahl and Timothy Arlen Brunner (appellants) each sought discovery of the complete computer source code for the Minnesota model of the Intoxilyzer 5000EN in their separate driving while intoxicated (DWI) criminal prosecutions. The district courts in both cases ordered the State to produce the computer source code within 30 days, or the courts would dismiss certain charges and find that the breath test results were hot admissible. The State appealed the discovery orders, and the court of appeals consolidated the actions and reversed both orders for production. State v. Underdahl, 749 N.W.2d 117, 121 (Minn.App. 2008).

We granted appellants' petitions for review concerning the district courts' discovery orders, and also asked the parties to brief two additional issues: (a) whether the State is required to show critical impact, under Minn. R.Crim. P. 28.04, in its pretrial appeal of the district court discovery orders, and (b) whether the State has shown that the district courts' pretrial orders at issue in these cases will have a critical impact on its ability to prosecute the defendants successfully. We answer both critical impact questions in the affirmative. Further, we affirm the court of appeals' decision to reverse the production order in appellant Underdahl's case. With respect to appellant Brunner, however, we reverse the court of appeals and reinstate the district court's order for State production of the complete computer source code for the Minnesota model of the Intoxilyzer 5000EN.

State v. Underdahl

On February 18, 2006, Dale Lee Underdahl was stopped on suspicion of driving while intoxicated and was arrested after performing poorly on field sobriety tests and failing a preliminary breath test. Underdahl agreed to a breath test performed with the Intoxilyzer 5000EN, the most recently approved breath-test instrument for the State of Minnesota. The Intoxilyzer 5000EN revealed an alcohol content of .23. Underdahl was charged in Dakota County District Court with third-degree driving while impaired (blood alcohol concentration of .20 or more), Minn.Stat. §§ 169A.20, subd. 1(5), 169A.26 (2008), and the complaint against him was later amended to include a charge of fourth-degree driving while impaired (under the influence of alcohol), Minn.Stat. §§ 169A.20, subd. 1(1), 169A.27.

Underdahl brought a motion for discovery, seeking State production of "a complete copy of the computer source and object codes for the Minnesota model of the Intoxilyzer 5000EN that was used to test the Defendant." The State opposed the motion, arguing that the source code was not relevant and not in the State's possession because the Intoxilyzer 5000EN's manufacturer, CMI, Inc., owned the source code. The district court granted the discovery request and ordered that a complete copy of the computer source code for the Minnesota model of the Intoxilyzer 5000EN be provided to Underdahl in 30 days, or any evidence of the Intoxilyzer 5000EN test would be excluded from the State's case and the charge of third-degree driving while impaired (.20 or more) would be dismissed.

State v. Brunner

On July 28, 2007, Timothy Arlen Brunner was stopped on suspicion of driving while intoxicated. Brunner agreed to an Intoxilyzer 5000EN breath test. That test revealed an alcohol content of .18. Brunner was charged in Dakota County District Court with first-degree driving while impaired (under the influence of alcohol within 10 years of three or more qualified incidents), Minn.Stat. §§ 169A.20, subd. 1(1), 169A.24 first-degree driving while impaired (blood alcohol concentration of .08 or more), Minn.Stat. §§ 169A.20, subd. 1(5), 169A.24 and driving after cancellation of a driver's license, Minn.Stat. § 171.24, subd. 5 (2008).

Brunner brought a motion for discovery of the computer source code for the Minnesota model of the Intoxilyzer 5000EN. The district court granted the motion and ordered the State to produce the complete computer source code within 30 days, or the court would dismiss the first-degree driving while impaired (over .08) charge and find that the test result was not admissible.

The State appealed the rulings of both district courts. The court of appeals consolidated the cases and reversed the district courts, concluding that Underdahl and Brunner had made "inadequate showings in the district court on the relevancy of the source code." State v. Underdahl, 749 N.W.2d 117, 121 (Minn.App. 2008). The court of appeals did not analyze whether the State had shown critical impact under Minn. R.Crim. P. 28.04. We accepted appellants' petitions for review, and also asked the parties to address whether the State was required to show critical impact in its pretrial appeal, and whether the State could show critical impact in these cases.

I.

We consider first whether the State was required to show critical impact in its pretrial appeal. Pretrial appeals by the State are governed by Minn. R.Crim. P. 28.04. We construe and interpret our rules of procedure de novo. State v. Barrett, 694 N.W.2d 783, 785 (Minn. 2005).

Minnesota Rule of Criminal Procedure 28.04, subd. 1(1), provides: "The prosecuting attorney may appeal as of right to the Court of Appeals . . . in any case, from any pretrial order of the trial court. . . ." The procedure for such an appeal is set out in subdivision 2, and requires:

The prosecuting attorney shall file with the clerk of the appellate courts a notice of appeal, a statement of the case . . . which shall also include a summary statement by the prosecutor as to how the trial court's alleged error, unless reversed, will have a critical impact on the outcome of the trial. . . .

Minn. R.Crim. P. 28.04, subd. 2(2). In State v. Webber, 262 N.W.2d 157, 159 (Minn. 1977), we held that a pretrial order will only be reversed if the State "demonstrates clearly and unequivocally that the trial court has erred in its judgment and that, unless reversed, the error will have a critical impact on the outcome of the trial." The operation of Rule 28.04, subd. 2 was reinforced by our decision in State v. Kim, where we upheld the critical impact requirement as a "fair and workable rule." 398 N.W.2d 544, 551 (Minn. 1987). The critical impact requirement has evolved into a "threshold issue," so that "`in the absence of critical impact we will not review a pretrial order.'" State v. McLeod, 705 N.W.2d 776, 784 (Minn. 2005) (quoting In re Welfare of L.E.P., 594 N.W.2d 163, 168 (Minn. 1999)); see State W. Scott, 584 N.W.2d 412, 416 (Minn. 1998) (noting the change to the Webber decision's order of analysis to require critical impact to be determined before deciding whether the trial court erred).

In the notices of appeal in these cases, the State did not assert critical impact; instead, the State stated that "Minnesota Appellate Courts have held that the critical impact requirement does not apply to discovery orders on pretrial appeal." The State then cited to a Minnesota Court of Appeals decision that exempts nonsuppression orders from the: critical impact requirement. State v. Renneke, 563 N.W.2d 335 (Minn.App. 1997). In Renneke, the State appealed a district court order compelling disclosure of a deputy's personnel file. Id. at 337. The court of appeals concluded that the State did not have to show critical impact in a discovery dispute because the critical impact requirement "originally applied specifically to suppression orders." Id. (citing State v. Solheim, 477 N.W.2d 785, 786-87 (Minn.App. 1991); State v. Cain, 427 N.W.2d 5, 9-10 (Minn.App. 1988)). The court of appeals held that discovery orders are exempt from the critical impact requirement, noting that rulings that directly impact the evidence admissible at trial can have a "critical impact" on the outcome of the trial, but this rationale does not extend to discovery orders. Id.

Recently, we cautioned that the court of appeals' rule in Renneke (exempting discovery orders from the critical impact requirement) has never been adopted by our court. State v. Rambahal, 751 N.W.2d 84, 89 (Minn. 2008). We further noted that the Renneke rule "appear[ed] to be at odds with our prior cases and the plain language of Minn. R.Crim. P.28.04," but we ultimately declined to rule on critical impact as the parties had not petitioned for review or briefed the issue. 751 N.W.2d at 89. We now hold that Minn. R.Crim. P. 28.04 requires the State to show critical impact in all pretrial appeals and there is no exception for an appeal from a discovery order. Our explanation follows.

We look first to the plain language of the rule. Rubey v. Vannett, 714 N.W.2d 417, 421 (Minn. 2006). Plain and unambiguous language must be followed. State v. Dahlin, 753 N.W.2d 300, 305 (Minn. 2008). The rule must be read as a whole and each section interpreted "`in light of the surrounding sections to avoid conflicting interpretations.'" Id. at 306 (quoting Am. Family Ins. Group v. Schroedl, 616 N.W.2d 273, 277 (Minn. 2000)).

Minnesota Rule of Criminal Procedure 28.04, subd. 1, allows the State to appeal from any pretrial order, while subdivision 2 requires these appeals to include a statement on "how the trial court's alleged error, unless reversed, will have a critical impact on the outcome of the trial." This language does not differentiate between suppression orders and discovery orders; the rule plainly requires all pretrial appeals to be accompanied by a statement of critical impact.

We have applied the plain language of the critical impact rule to discovery and nonsuppression orders in at least two decisions. In State v. Hejl, the State appealed a district court order to produce the transcript of grand jury proceedings to a defendant. 315 N.W.2d 592, 592 (Minn. 1982). We held that the State failed to demonstrate that an error in the order would have a critical impact on the defendant's prosecution. Id. at 593. In State v. Barsness, the district court ruled that evidence of a defendant's IQ was admissible, a ruling that the court of appeals reversed. 473 N.W.2d 828, 828 (Minn. 1990). We said that the court's pretrial evidentiary ruling could only be reversed if the State demonstrated the court had erred and that the error would have critical impact. We held that the State had not established critical impact. Id.

While not central to our decision, the rule we affirm today fulfills the original purpose behind Minn. R.Crim. P. 28.04. Historically, appeals by the government in criminal cases were "`unusual, exceptional, not favored.'" Arizona v. Manypenny, 451 U.S. 232, 245, 101 S.Ct. 1657, 68 L.Ed.2d 58 (1981) (quoting Will v. United States, 389 U.S. 90, 96, 88 S.Ct. 269, 19 L.Ed.2d 305 (1967)). To ensure individuals were free from harassing litigation by the State, the government traditionally had no authority to appeal without express legislative authorization. See United States v. Sanges, 144 U.S. 310, 315, 318, 12 S.Ct. 609, 36 L.Ed. 445 (1892). Minnesota did not allow prosecutorial appeals until 1967, when statutes were enacted that gave the State a limited right to pretrial appeal and formed the basis for the critical impact requirement. See Minn.Stat. §§ 632.11, 632.12 (1967) (repealed 1979). In 1975, the Minnesota Rules of Criminal Procedure superseded these statutes; the rules broadened the scope of appealable pretrial orders, but still required a showing of critical impact. See Minn. R.Crim. P. 23.08 (1975) (current version at Minn. R.Crim. P. 28.04). We continued to recognize that the rules on government pretrial appeals must be strictly construed, as the appeal could occur as "the defendant is awaiting trial, presumed innocent, and possibly confined." State v. Barrett, 694 N.W.2d 783, 787 (Minn. 2005).

We turn to the question of whether the State has demonstrated critical impact in the two cases before us. When the State appeals a pretrial order, it must show clearly and unequivocally (1) that the district court's ruling was erroneous and (2) that the ruling will have a "critical impact" on the State's ability to prosecute the case. State v. McLeod, 705 N.W.2d 776, 784 (Minn. 2005). Critical impact, the threshold question, is intended to be a "`demanding standard,'" but with some flexibility. Id. (quoting State v. Zanter, 535 N.W.2d 624, 630 (Minn. 1995)). The State can show critical impact when complying with an order "significantly reduces the likelihood of a successful prosecution." Id. (citing Kim, 398 N.W.2d at 551). The State does not have to show that conviction is impossible after the pre-trial order — only that the prosecution's likelihood of success is seriously jeopardized. In re L.E.P., 594 N.W.2d at 168.

When examining critical impact, the State's admissible evidence will be viewed as a whole to determine what impact the pretrial order will have on the prosecution's case. Id. Evidence unique in nature and quality is more likely to satisfy the critical impact requirement. Id.

The State argues that the discovery orders requiring production of the Intoxilyzer code will have a critical impact on the prosecution because the orders exclude the Intoxilyzer test results from trial if the source code is not produced. The State argues that if the test results are excluded, charges against both appellants will be dismissed because Underdahl's charge of third-degree driving while impaired (.20 or more) and Brunner's charge of first-degree driving while impaired (over .08) are based on the test results. See Minn.Stat. § 169A.20, subd. 1(5). The State also claims it would lose important evidence in the remaining DWI charges. Appellants argue that suppression of the test results will not have critical impact, because the State can still successfully prosecute appellants on the charges that would remain in both cases. See Minn.Stat. §§ 169A.20, subd. 1(1), 171.24, subd. 5.

We agree with the State that the pretrial orders will have a critical impact on the State's ability to successfully prosecute these cases. Although we have never before held that a discovery order can have critical impact, see Hejl, 315 N.W.2d at 593, these orders keep the Intoxilyzer test results from coming into evidence if the State does not comply with the discovery orders. In addition, an order that dismisses DWI charges, even when other charges remain, will have a critical impact on the prosecution's case. See State v. Hicks, 301 Minn. 350, 353, 222 N.W.2d 345, 347 (1974). In Hicks, a pretrial order suppressed the results of a blood alcohol test in criminal charges of driving while under the influence and driving with .10 percent or more blood alcohol content. Id. at 351-52, 222 N.W.2d at 347. The prosecution was required to meet our previous standard set forth in Minn.Stat. § 632.11 (1974), which required the prosecutor to show that the order "`effectively prevented the chance of a successful prosecution.'" 301 Minn, at 352, 222 N.W.2d at 347 (citation omitted). We held the pre-trial order prevented the chance of successful prosecution of the driving with .10 percent or more blood alcohol content, so the order was appealable. Id. at 353, 222 N.W.2d at 347.

State v. Hicks controls our conclusion here. The pretrial orders would suppress the breath tests and expressly dismiss certain charges as a result of nonproduction, keeping the State from being able to prosecute those charges at all. Further, the breath test results cannot be duplicated by other evidence. We therefore hold the district court discovery orders meet the critical impact test because the exclusion of the breath test results will significantly reduce the likelihood of a successful prosecution on a charged offense.

II.

We next turn to whether the district courts abused their discretion in concluding that the computer source code was relevant and otherwise discoverable under Minn. R.Crim. P. 9.01, subd. 2. Rule 9 of the Minnesota Rules of Criminal Procedure governs discovery in criminal cases. Rule 9.01, subd. 1, describes what must be disclosed by the prosecution without a court order. Rule 9.01, subd. 2, details the circumstances under which the court may use its discretion in ordering additional discovery. In relevant part, Rule 9.01, subd. 2(3), states:

Upon motion of the defendant, the trial court at any time before trial may, in its discretion, require the prosecuting attorney to disclose to defense counsel and to permit the inspection, reproduction or testing of any relevant material and information not subject to disclosure without order of court under Rule 9.01, subd. 1, provided, however, a showing is made that the information may relate to the guilt or innocence of the defendant or negate guilt or reduce the culpability of the defendant as to the offense charged.

Minn. R.Crim. P. 9.01, subd. 2(3) (emphasis added).

A district court judge has "`wide discretion to issue discovery orders,'" and normally an order will not be overturned without clear abuse of that discretion. In re Comm'r of Pub. Safety (Underdahl I), 735 N.W.2d 706, 711 (Minn. 2007) (quoting Shetka v. Kueppers, 454 N.W.2d 916, 921 (Minn. 1990)). To find an abuse of discretion, an appellate court must conclude that the district court erred by making findings unsupported by the evidence or by improperly applying the law. Id.

We have not previously stated what showing is required to support a district court's conclusion that information may re-late to a defendant's guilt or innocence in a DWI case. But we have described that showing in cases where the defendant has requested to review confidential information. In those cases, we have required "some plausible showing that the information sought would be both material and favorable to his defense." State v. Hummel, 483 N.W.2d 68, 72 (Minn. 1992) (citation omitted) (internal quotation marks omitted); accord State v. Evans, 756 N.W.2d 854, 872-73 (Minn. 2008). In Hummel, we overturned the district court's discovery order of a confidential file because the defense offered no theories on how the file "could be related to the defense or why the file was reasonably likely to contain information related to the case." 483 N.W.2d at 72.

In his discovery motion, appellant Underdahl requested a copy of the Intoxilyzer source code or the exclusion of the breath test result if the State failed to produce the source code. Underdahl's motion contained no other information or supporting exhibits related to the source code. At an omnibus hearing on October 17, 2007, Underdahl argued that a jury in a DWI case is asked to determine whether a breath test result is valid, and the only way for Underdahl to challenge that validity "is to go after the testing method itself." The district court found that the jury instructions in a DWI case require the jury to evaluate the reliability of the testing method in determining the blood alcohol concentration level. Because the Intoxilyzer 5000EN provides the only evidence of alcohol concentration, the court found that evidence regarding the operation of that instrument is relevant.

Appellant Brunner submitted a memorandum and nine exhibits to support his request for the source code. The memorandum gave various definitions of "source code." The first exhibit was the written testimony of David Wagner, a computer science professor at the University of California in Berkeley, which explained the source code in voting machines, the source code's importance in finding defects and problems in those machines, and the issues surrounding the source code's disclosure. The next exhibits detailed Brunner's attempts to obtain the source code, both from the State and CMI. The last exhibit was a copy of a report prepared on behalf of the defendants in New Jersey litigation about the reliability of New Jersey's breath-test machine. See State v. Chun, 194 N.J. 54, 943 A.2d 114 (2008). The report analyzed the New Jersey machine's computer source code and uncovered a variety of defects that could impact the test result. Based on Brunner's evidence, the district court found that the integrity of the source code is essential to the scientific reliability of the Intoxilyzer 5000EN test result. Further, the jury instructions asked the jurors to assess the reliability of the testing method, which could not be done without Brunner having access to the software controlling that testing process.

Although broad discretion is given to district courts in discovery matters, the district court in appellant Underdahl's case abused its discretion in finding the source code relevant and related to his guilt or innocence. Underdahl made no threshold evidentiary showing whatsoever; while he argued that challenging the validity of the Intoxilyzer was the only way for him to dispute the charges against him, he failed to demonstrate how the source code would help him do so. As in Hummel, Underdahl advanced no theories on how the source code "could be related to [his] defense or why the [source code] was reasonably likely to contain information related to the case." 483 N.W.2d at 72. We hold that, even under a lenient showing requirement, Underdahl failed to make a showing that the source code may relate to his guilt or innocence.

Brunner submitted source code definitions, written testimony of a computer science professor that explained issues surrounding the source codes and their disclosure, and an example of a breath-test machine analysis and its potential defects. Brunner's submissions show that an analysis of the source code may reveal deficiencies that could challenge the reliability of the Intoxilyzer and, in turn, would relate to Brunner's guilt or innocence. Therefore, we hold that the district court in Brunner's case did not abuse its discretion in concluding that the source code may relate to his guilt or innocence.

III.

We next determine whether the district courts' findings that the State had possession or control of the source code were clearly erroneous. The court of appeals did not reach this issue because it reversed both district courts' discovery orders based on the grounds of relevance. Minnesota Rule of Criminal Procedure 9.01, subd. 2(1), requires prosecuting attorneys to assist the defendant in seeking access to matters that are within the "possession or control" of the State. Both district courts found that the State is the owner of the source code for the Minnesota model of the Intoxilyzer 5000EN, relying on the request for proposal (RFP) issued by the State when replacing the previous version of its breath-test instrument. The State argues that the district courts erred; it asserts that our holding in Underdahl I is distinguishable because the Underdahl I court was reviewing this question under the higher threshold of a writ of prohibition, and further contends that the RFP actually gives appellants, not the State, the right to access the source code.

In Underdahl I, the State had been ordered to produce the source code in appellant Underdahl's implied consent hearing. 735 N.W.2d at 709. The Commissioner of Public Safety petitioned the court of appeals for a writ of prohibition to prevent the district court from enforcing the order, a writ that can be issued if the mandated discovery "is clearly not discoverable and for which there is no adequate remedy at law." Id. at 711. We concluded that the Commissioner had failed to meet his burden of demonstrating that the source code was "clearly not discoverable" because the source code was in "possession, custody or control" of the State; the Commissioner had conceded that the State owned some of the source code, a concession supported by the express copyright language in the RFP. Id. at 712.

We similarly conclude that the district courts did not abuse their discretion in finding the State had possession or control of the source code under Minn. R.Crim. P. 9.01, subd. 2(1). The RFP language cited by the district courts supports their conclusions that the State had possession of the source code. The State's arguments that appellants have access to the source code are also unpersuasive, because Rule 9.01, subd. 2(1), only speaks to the State's obligation to assist a defendant in seeking access to material the State possesses, aside from the defendant's possible access. We therefore hold that it was not an abuse of discretion for the district courts to find that the source code was in the possession or control of the State.

In appellant Underdahl's case, we affirm the court of appeals and reverse the production order in his case. With respect to appellant Brunner, however, we reverse the court of appeals and reinstate the district court's order for State production of the complete computer source code for the Minnesota model of the Intoxilyzer 5000EN.

Affirmed in part, reversed in part, and remanded.