It is an iconic image of the struggling artist in America: A musician wielding a guitar, saxophone, cello, or other instrument serenading commuters outside a metropolitan subway system. Their reward is whatever cash or coins are voluntarily dropped into an open instrument case.

That’s how guitarist Alex Young was earning money last year, playing for a steady stream of riders on the Washington, D.C. Metro system.

But now his career as a mass transit minstrel may be over.

Police officers with the Washington Metropolitan Area Transit Authority have twice threatened to arrest Mr. Young. The threatened arrests were not for playing his guitar at the subway station, they were for playing his guitar at the subway station with an open guitar case.

The officers said that by soliciting tips with an open guitar case Young was engaging in a prohibited commercial activity on Metro property.

Young is fighting back. In a lawsuit filed in federal court in Washington, he says he has a First Amendment right to play his guitar in public areas – with an open guitar case.

US District Judge Beryl Howell has scheduled a hearing for Thursday, Aug. 14.

“An open guitar case or tip jar is a silent reminder that artists need to make a living and, more broadly, that survival of the arts depends on society’s willingness to support artists financially,” Young’s lawyer, Jeffrey Light, wrote in his brief.

“A passerby will certainly understand the message conveyed by a ‘starving artist’ performing on the street with an open guitar [case] as distinct from the message conveyed by a professional orchestra holding a free symphony [concert] in the park. And that is Mr. Young’s intention,” Mr. Light wrote.

Light is asking Judge Howell to issue an injunction blocking Metro officials from enforcing their anti-busking policy.

Metro regulations permit individuals to engage in free speech activities at Metro stations, but they must not interfere or impede rider access. Regulations require that free speech participants remain at least 15 feet from entrances, escalators, fare gates, and fare card machines.

Young says he complies with these rules. But Metro police say he is also barred from collecting tips.

Lawyers for the Metro system insist that Young is allowed to play his guitar at the stations. But that is not all he is doing, they say.

“It is his request of patrons that he be paid some unspecified amount which converts his activity into a commercial transaction. This is the prohibited conduct,” said Kathryn Pett, WMATA general counsel, in her brief to the judge.

“There is nothing in that conduct which expresses an idea or conveys a particularized message and, therefore, nothing that constitutes speech,” Ms. Pett said.

“[Young] is free to play his guitar beyond the 15-foot restriction,” she said. “He has neither been asked to leave any of the rail stations nor threatened with arrest for playing his guitar.”

In an affidavit filed with the court, Young said he does not ask people to contribute. “Although I accept donations, I do not request them, either verbally or in writing. I do not ask that any passersby pay me money for performing music,” he said.

“Not being able to accept donations would be harmful not only to my ability to make a living, but it would also change the message that I am trying to convey,” he said.

“By having an open guitar case (or tip jar), I mean to express that society should support artists,” he said in the affidavit.

Young said playing without an open guitar case would suggest that he was playing for his own enjoyment, as a hobby. It is not a hobby, he said.

“It is important for me to have an open guitar case (or tip jar) so that people understand that if they want to have art and music in the world, artists need to be supported,” Young said.

In asking the judge to uphold the Metro regulation, Pett said the authority’s ban on commercial activity is aimed at preserving clear access for the 500,000 passengers who ride the Metro each day.

“To permit commercial activity would most likely result in persons obstructing ingress and egress to the stations by selling their wares and by spreading out on the sidewalk, as [Young] has done and proposes to do with his guitar case,” she said.

“Plaintiff has ample avenues of communication available to solicit money from persons by word or deed, other than on WMATA property,” Pett said.

Young’s lawsuit is being funded by the non-profit civil liberties group, The Rutherford Institute.

“America’s founders ensured that expressive activities, no matter what the medium – whether it’s spoken, written, sung, painted, or played – are clearly protected by the First Amendment,” Rutherford Institute President John Whitehead said in a statement.

“At a time when the government spies on its citizens, monitors their activities, treats them like suspects, and denies them fundamental rights, it’s not surprising that the government would clamp down on free speech activities, even of the musical variety,” Mr. Whitehead said.

“If we are to have any hope of salvaging our freedoms, it is more critical than ever that we stand up for the rights of those who dare to speak up and challenge the status quo, whether they be artists, activists, or government whistleblowers,” he said.

The case is Young v. Sarles (14cv1203).