In the "Marshal Law" comic-book series, Law is the last name of a law- enforcement officer "with superpowers in the city of San Futuro, the near- future metropolis built from the ruins of San Francisco following a massive earthquake," according to Wikipedia. I've never read these comics, but they offer a satirical take on superhero characters and our government.
Perhaps some Republican officials mixed up the Marshal Law character with the term "martial law"—defined by Investopedia as "the substitution of a civil government by military authorities with unlimited powers to suspend the ordinary legal protections of civilian rights."