Amid honking from cars below, Daniel Martins was doing what he often did on Fridays, advocating for the impeachment of President Barack Obama from a pedestrian bridge over the Long Island Expressway.

On the sunny day last June, however, the Hofstra University student was confronted and arrested for disorderly conduct and criminal nuisance by Nassau County police who claimed his signs and flags might cause a car crash.

The criminal case was dismissed on free speech grounds in December and Martins now is seeking $2 million in a federal lawsuit, alleging the arrest was illegal and intended to stop his exercise of First Amendment-protected rights.

“It wasn’t a problem for anybody but the police,” says attorney Thomas Liotti, a two-time Obama voter representing Martins. “It wasn’t distracting. I don’t think anyone took much note of it because these things happen all the time in New York.”

Liotti says if flag burning and neo-Nazi parades are protected by the First Amendment, so, too, is Martins’ speech. “It’s free speech for everyone, that’s what we’re trying to support here,” he says.

The attorney sees the arrest as a clear constitutional violation worthy of swift redress, an opinion bolstered by Nassau District Court Judge Sharon Gianelli, who dismissed the criminal case against Martins.

“Defendant’s conduct is protected by the U.S. Constitution and therefore not criminal,” she ruled. “His conduct is akin to protestors on a sidewalk holding signs. ... They do it to get the attention of passersby, including drivers as well as pedestrians, in order to form support for their positions. If every protestor were arrested and hauled off to jail, that would run afoul of the rights and freedoms that we have fought for throughout our history and which define the very identity of our great union.”

Martins, who filmed the events leading to his arrest, tells U.S. News the lawsuit is about more than just money. The Students for Liberty member also is looking to punish those responsible for his arrest and affirm that such protests are protected by the Constitution.

“When your rights are being violated, the person responsible for it should be punished. People automatically assume guilty when they see you have been arrested, and that’s not something I want on my head for the rest of my life,” he says. “I’m doing this for other Americans. People protest every day. I don’t want them to go through what I had to go through.”

Now a senior at Hofstra eyeing law school, Martins has only been once to the overpass to protest since going to jail, on June 6 this year, the anniversary of his arrest. He says police didn’t show up.

Liotti is working the case on a contingency basis, meaning free of charge unless there’s a financial award. Martins is paying court fees, for which he set up a GoFundMe page. The $2 million request for punitive and compensatory damages wasn't included in the lawsuit as originally filed.

Clay Calvert, director of the University of Florida’s Marion B. Brechner First Amendment Project, says the case may prove less than straightforward.

The Associated Press, covering the case last year, reported that the state Department of Transportation allows municipalities to permit roadside signs. Content-neutral restrictions would be allowed, Calvert says, but only if the rules are applied in an even-handed way.

“For instance, if they allowed ‘Support Obama’ banners but not ‘Impeach Obama’ banners, then that would be a clear violation of the First Amendment,” he says. “That would be viewpoint-based discrimination, which is always unconstitutional.”

A spokeswoman for the Nassau County Police Department, a named defendant alongside individual police officers and the county government, says “we don’t comment on any open litigation” and was unable to say if there are specific county-wide rules for roadside signs.

Though he believes the case could be settled outside court, Liotti says it’s also possible that Nassau County officials would feel “we need to stop all this free speech and people putting up signs over the expressway and so on.”

In the self-shot video before his arrest, Martins offers to remove the signs affixed to a chain link fence and hold them himself, but was rebuffed. "I'm willing to compromise," he said. An officer declined to accept the offer, suggesting the protest was "the same type of thing" as drunk driving.