According to a 2012 decision by the US Supreme Court, Abel Fields's actions are protected by the First Amendment.
In the fictitious case study scenario of Abel Fields, he claimed to have received a Purple Heart for wounds suffered in combat, when in fact he had never served in the military. He asserted his claim as a freedom of speech issue.
In a real-life decision by the US Supreme Court, United States v. Alvarez, the the Court struck down the Stolen Valor Act of 2005 (signed into law by President G.W. Bush in 2006). The law had criminalized false statements about having a military medal. By a 6-3 majority, the Supreme Court determined that the Stolen Valor Act was unconstitutional under the First Amendment's protection of free speech.