Collateral Incentives to Arrest
The power to arrest is one of the most fundamental forms of the state’s power to coerce. Historically, an arrest—i.e., taking an individual into state custody against his will—was plainly intended to vindicate a singular societal interest in prosecuting for particular crimes that prompted the arrest. That principle was largely honored in practice and reflected in the law: for instance, in the nineteenth, and even into the twentieth century, an officer was liable for unlawful arrest or imprisonment if an arrest was not in fact followed by prosecution.
In modern times, the authority to arrest is not so limited by law. It is universally acknowledged that modern police have a great deal of discretion when it comes to deciding whom to arrest and for what offenses. Police often use that discretion for purposes disconnected from the interest in prosecution for the behavior that formally justified the arrest, and prosecution does not in fact follow a great many arrests. Police may arrest for petty violations simply to make their presence felt on the streets. They may arrest on probable cause for a minor crime to investigate their suspicion of other, more serious crimes, for which probable cause is absent. They may arrest simply to harass certain people, or select which of many violators to arrest on arbitrary, unjustifiable grounds such as race. Pretextual arrests—i.e., arrests motivated primarily by something other than the desire to pursue charges for the behavior that amounts to probable cause—are exceedingly common. Under modern Supreme Court precedent, officers’ subjective motivations, no matter how objectionable, do not make an arrest unconstitutional under the Fourth Amendment, so long as probable cause for an arrest exists objectively. The Court also recognized police authority to arrest even for the pettiest violations that carry no jail time, and ruled that an arrest is constitutional even if there were no probable cause to arrest for the offense identified by the arresting officer, so long as probable cause for some offense existed objectively.
In the context of our expansive criminal and traffic codes, these and other decisions make it easy for police to use arrests to pursue non-prosecutorial objectives. Yet, as late as the 1960s, criminal law experts such as Wayne LaFave maintained that arrests “made for purposes other than the sole legitimate objective of prosecution,” although common in practice, represented misuses of that discretion to arrest. Although Supreme Court decisions signal some erosion of the historical purpose that justified the arrest power, we should not conclude that they represent a complete abdication of that principle. Instead, they are a concession to practical limits of the law: courts are ill-equipped to “plumb the minds” of police for “impure plots,” which makes it difficult to impose meaningful sanctions for pretextual arrests. As I argue in a recent article, although it is no longer required by law, the aspiration that arrests be made not merely when any probable cause exists but for probable cause—i.e., to pursue charges based on the conduct that gave rise to probable cause —remains at the core of policing jurisprudence.
While mixed motives for making arrests are commonplace and unavoidable, policy-makers ought to think twice about policy innovations that create further incentives for pretextual arrests. And a subset of such incentives, which may be called “collateral,” should be of a particular concern. Two recent on-arrest screening regimes—the Department of Homeland Security’s Secure Communities program, and mandatory on-arrest DNA collection laws—illustrate the reasons for that concern. In addition to incentivizing the misuse of discretion in the exercise of the arrest power, these innovations incentivize lower quality arrests and unwarranted inequality in arrest patterns, likely along ethno-racial lines.
On-arrest Immigration Screening and DNA Collection
Under Secure Communities, fingerprints taken at arrest by any local law enforcement agency (LEA) are automatically screened against the DHS databases of immigration violators. If a fingerprint match leads immigration officials to initiate deportation proceedings, a detainer is issued to the LEA requesting suspect’s detention for up to 48 hours for Immigration and Customs Enforcement to assume custody. Prior to the program, local law enforcers’ ability to discover arrestees’ immigration status or to trigger deportation proceedings was limited, requiring more time and effort. Although DHS now claims that it ended Secure Communities, replacing it with the Priority Enforcement Program (PEP), the transmission of fingerprints and screening of all arrestees and the potential for deportation, regardless of criminal charges for the crime of arrest, remain in place.
The federal government and 30 states have recently enacted laws providing for involuntary DNA collection from some arrestees, requiring no warrant or additional justification. A digital profile of the arrestee’s DNA sample is collected and added to the DNA database and analyzed for matches to existing profiles of DNA from arrestees and convicts as well as forensic samples from unsolved crime scenes. In some jurisdictions, only a subset of felonies trigger DNA collection, while in others, the set of crimes extends to all felonies and even some misdemeanors. In Maryland v. King, the Supreme Court upheld a version of such a law, noting that it furthers the state interest in identification of the individual and his criminal history. DNA collection also enables police to solve unsolved crimes by means of matches (“cold hits”) between the arrestee’s DNA and that collected at an unsolved crime scene. Importantly, DNA collection also serves simply to insert DNA profiles into the database, so as to deter and detect any further crimes by the DNA donor.
“Collateral” Incentives
The prospects held out by these screening regimes—deportation, cold hits, and crime deterrence—provide law enforcers with incentives that may influence how they exercise their discretionary authority to arrest. We might call these incentives “collateral” because (i) they hold out benefits that are largely uncorrelated with the suspect’s probability of guilt for the crime of arrest, and (ii) the probability of reaping these benefits is largely independent of the suspect’s guilt of, or prosecution for, the crime of arrest. These characteristics distinguish these incentives from some other common ulterior purposes for arrests.
Non-correlation means that arrests of some suspects are made more attractive than of others, for reasons not correlated to their guilt, culpability, or the state’s interest in pursuing charges for the crime of arrest. By and large, police who are attracted by the benefits offered by screening are not motivated to arrest guiltier or more culpable suspects. In the case of immigration screening, police might be tempted to use their discretion to arrest those who are likely deportable for any available arrestable violation. And immigration status is generally uncorrelated with the likelihood of guilt of most crimes of arrest, whether police focus on foreigners or Hispanics as those most likely to be deportable. The emerging scholarly consensus is that immigrants, whether authorized or not, are less prone to crime than natives. And while Hispanic involvement in crime is understudied due to a historic dearth of ethnicity data, research tends to show that Hispanic involvement in crime is not clearly higher, and in some cases notably lower, than that of non-Hispanics.
DNA collection laws, in turn, create additional incentives for police to arrest suspected serious repeat offenders, or the “usual suspects,” since criminals identified through DNA matches have longer and more serious criminal histories than those identified through other means. The usual suspects, as many justifiably worry, are more often than not identified by the police by reference to race. However, the degree to which race actually correlates with repeat offending varies across crimes. As prominent sociologists Sampson and Lauritsen note, “there are certain offenses for which each [race] is overrepresented.” Profiling on race because of its perceived correlation with serious violent criminal offending may correlate with the probability of guilt of some violent crimes, but not with the probability of guilt for other crimes that trigger DNA collection. For example, police may be more likely to arrest minority offenders, perceived to be repeat serious offenders, for crimes such as identity theft (a crime triggering collection in Louisiana), perjury (triggering collection in Ohio), and eavesdropping (triggering collection in South Carolina). As the set of crimes triggering DNA collection becomes broader, focusing on the usual suspects becomes less and less likely to produce guiltier arrestees for more and more arrests.
A lack of correlation would be less problematic if police still had to worry about the lawfulness of the arrest, or the strength of probable cause, to reap the benefits created by these screening regimes. For example, scholars and commentators have long criticized the search incident to lawful arrest (SILA) doctrine: the automatic right to conduct searches incident to arrest holds out the lure of discovering evidence of a (usually more serious) crime for which police lack a sufficient quantum of suspicion, when arresting for another, usually minor crime. However, even if suspicion as to the more serious crime does not correlate with the likely guilt of the crime of arrest, the police must still care about the arrest’s lawfulness to avoid the suppression of evidence discovered through illegality. By contrast, the prospect of an arrestee’s deportation is unaffected by the possibility that the arrest is illegal. That is because no rule of law deprives the police of the benefits created by screening if an arrest is unlawful. Immigration screening typically occurs before the arrest’s lawfulness is determined and a detainer may issue before the legal basis for the arrest is evaluated. Moreover, even if the identification of an individual as an immigration violator was obtained through an unlawful arrest, his identity (including his immigration file) will not ordinarily be suppressed in a deportation hearing.
The degree to which the benefits of DNA collection depend on the lawfulness of the arrest varies across jurisdictions. In close to two-thirds of the states, DNA collection occurs before probable cause is determined. And in many of these, police would not lose the benefit of a DNA match in a future prosecution, even if the arrest that yielded the match was unlawful. Unlike Maryland’s law, which was upheld in King, many courts in other jurisdictions hold that “the exclusionary rule,” which operates to suppress evidence obtained illegally, “does not apply to evidence to establish the defendant’s identity in a criminal prosecution.” Since the defendant’s “identity” has come to include not just a name, but also criminal history, under this approach, a DNA match discovered after an illegal arrest can still be used to support future prosecution. Moreover, because most states place the burden of expunging a wrongfully obtained DNA profile on the individual, DNA profiles from those wrongfully arrested are far more likely to remain in the system than to be expunged following illegal arrests or acquittals.
Implications of Collateral Incentives
Because screening regimes such as these set up collateral incentives to arrest on bases unrelated to the guilt of the crime of arrest, we should expect that they have some adverse effects on arrest quality, as well as a redistributive effect on the pool of arrestees. Experts often address so-called “statistical discrimination,” or the practice of using group traits as one basis for selecting targets for enforcement on account of perceived disparities in offending between identifiable groups. This practice is particularly controversial when the group trait is race. Controversial though it is, as Albert Altschuler put it, there is a trade-off between equal treatment and “efficient” enforcement such as high-quality arrests. Unlike “pure” statistical discrimination, however, collateral incentives do not “trade off” inequality for arrest quality. Because the traits on which police are incentivized to profile are those which would capture benefits such as immigration screening or DNA collection, and not the primary benefit of an arrest, at least for a subset of arrests, collateral incentives are likely to result in a compromise with respect to both.
Immigration enforcement and solving cold cases certainly constitute important public interests. But seizing on the moment of arrest to advance these interests divert arrests from their historic, primary purpose, inviting unwarranted inequalities in enforcement and lower quality arrests. The power to deprive individuals of their liberty is accompanied by the power to use lethal force. This further counsels caution with regard to policies that seek to free-ride on arrests to advance other goals. This is especially so if these public policy goals may be substantially furthered otherwise. Most, if not all, of the advantages of database screening regimes are captured by screening and analysis of fingerprints and DNA at conviction, which ensures that state actors are committed to the prosecution of the crime of arrest and lessens the distortion of arrest incentives.