Here’s the crux of the legal dilemma:
That case, Butler v. Perry, is the “closest case to the government forcing somebody to work and being the defendant in a 13th Amendment case,” LeRoy said. But Butler was a private citizen threatened with imprisonment for not working, whereas the government has the authority to call in employees to work without pay under the Antideficiency Act. The act prohibits the executive branch from spending money Congress hasn’t yet appropriated —including wages.
The problem with the law, though, as Todd Dickey, an assistant professor at Syracuse University pointed out in a commentary for The Washington Post, is that it runs contrary to the Fair Labor Standards Act, which lays out minimum-wage requirements for government employees. That’s an argument federal employees have made successfully in the past, Dickey noted.
But as for involuntary servitude, LeRoy said there isn’t a precedent for the situation the federal employees have presented. At the same time, he said, a government shutdown has also never lasted this long, putting these federal employees in uncharted legal territory.
“If it’s true that somebody is threatened with termination if they don’t show up for a job when they’re not being paid today, that’s an unsettled legal issue — a court could rule that is legal coercion,””LeRoy said. “Losing your job for not working without pay is, in common vernacular, coercion. Whether that satisfies the legal definition of coercion is an open question.”
The end of the article basically says the longer this goes on, the stronger their case is.