In Fleetwood Trailer, 389 U.S. 375, 88 S.Ct. 543, the Supreme Court was required to determine whether the employer violated the Act when it hired six new employees who had not previously worked for the company instead of six former strikers who had applied for reinstatement.
Holding an injunction banning picketing was "justified only by the violence that induced it and only so long as it counteracts a continuing intimidation"
Holding that while an employer is not obligated to discharge permanent replacements to make room for returning economic strikers, the employer must place the former strikers on a preferential recall list