And it is even more difficult still if the defendant had – and acted in accordance with – a reasonable interpretation of the vague or ambiguous statute, regulation or contract provision. A concurring opinion in a Supreme Court decision issued this week indicates that civil liability in such situations may also be Constitutionally suspect.

Courts have held that a defendant cannot “knowingly” submit a false claim when it certifies compliance with an ambiguous contract provision based on its objectively reasonable interpretation of that ambiguous or vague provision, and when the government had not officially warned the defendant away from its otherwise objectively reasonable interpretation of that provision. This makes sense because it is unfair to hold a defendant liable for a knowingly or recklessly made false statement when there is more than one reasonable interpretation of the applicable regulation and the government failed to communicate its interpretation.

In criminal cases, courts have long held that criminal statutes may be void for vagueness in order to guarantee that ordinary people have “fair notice” of the conduct a statute proscribes. Papachristou v. Jacksonville, 405 U. S. 156, 162 (1972). In recent years, the Supreme Court has applied this in immigration cases. Two years ago, the Court held that the Armed Career Criminal Act’s definition of “violent felony” was so vague as to violate the due process clause. Johnson v. United States, 576 U. S., at ___–___ (slip op., at 13–14).

The Court recently returned to the issue in another immigration case, Sessions v. Dimaya, found that a “crime of violence” was unconstitutionally vague. Many reports have focused on the unusual voting make up: the majority opinion was authored by Justice Elena Kagan, who was joined by Justices Ruth Bader Ginsburg, Stephen Breyer, Sonia Sotomayor and, in large part, Neil Gorsuch

For False Claims Act practitioners, Justice Gorsuch’s concurring opinion is more interesting. As summarized by SCOTUSblog (emphasis added):

Gorsuch concurred in part and concurred in the judgment. He emphasized at the outset that “[v]ague laws invite arbitrary power.” He defended the originalist foundations for vagueness challenges that Justice Clarence Thomas questioned at length in his dissent, tracing the history of those challenges back to Blackstone’s condemnation of vague statutes and the “tradition of courts refusing to apply vague statutes.” He further noted that the concern with vague statutes was not “confined to the most serious offenses like capital crimes.” Addressing the government’s argument that a more lenient standard of review should apply in civil cases, Gorsuch would have gone even further than the plurality. He suggested that provisions of civil laws should be scrutinized closely for vagueness even outside the deportation context: “Why, for example, would due process require Congress to speak more clearly when it seeks to deport a lawfully resident alien than when it wishes to subject a citizen to indefinite civil commitment, strip him of a business license essential to his family’s living, or confiscate his home?”

Justice Gorsuch’s concurring opinion reflects a growing sentiment in False Claims Act and other cases that defendants cannot, and should not, be held liable in the face of vague and ambiguous statutes, regulations and contracting provisions.