The 2006 congressional law makes it a crime for someone to falsely boast, verbally or in writing, that they're the recipient of military honors.
The justices must decide whether the First Amendment protects not just freedom of speech, but a right to lie about such honors.
The case involves Xavier Alvarez who won a seat on a California water district board.
In 2007, he falsely declared he was a retired Marine who had received the Medal of Honor in 1987.
He was convicted and fined five-thousand dollars.
The High Court is expected to rule on the issue this summer.
(Copyright 2012 by VERTEXNews/Newsroom Solutions)