The protests and rioting that have followed Saturday's shooting death of unarmed black teenager Michael Brown by police in Ferguson, Mo., have raised multiple issues. One of them concerns the rights of citizens and journalists to film law enforcement.
Reports from Ferguson suggest that law enforcement officers -- many from the St. Louis County Police Department -- have become aggressive in their requests for members of the media and others to stop filming with their mobile phones and other cameras.
Washington Post reporter Wesley Lowery, who was arrested Wednesday along with the Huffington Post's Ryan Reilly, said he was brusquely asked by the police to stop filming.
Over the last few years, as smartphones have become almost ubiquitous, police officers across the US have occasionally responded with anger to being filmed in the course of their duty. Some situations seem trivial, others much more serious.
Police have even been accused of erasing bystanders' mobile phone footage of their behavior.
The law, though, has only really been tested since 2011. And legal decisions move far more slowly than technological developments.
In essence, citizens do have the First Amendment right to film police officers in their line of duty in any public place. The one caveat is that those filming shouldn't be obstructing the officers in the process.
"As long as you stay behind the police's yellow lines, you have the right to film or photograph them," Clay Calvert, a University of Florida professor of mass communication, told me Thursday.
When it comes to the two reporters who were arrested, Calvert said he could see no evidence that the journalists were somehow impeding the police in their line of work.
First Amendment rights are, however, sometimes treated in a more fluid manner by police acting under extreme stress or merely attempting to unreasonably assert their authority. Some police officers, Calvert said, prefer that the First Amendment issue is decided in a court, rather than debating it on a street.
In the case, for example, of a traffic stop, when police have no idea with whom they might be dealing, gray areas arise -- at least in a police officer's point of view. The individual may be armed. There may be other safety concerns.
One case that remains up in the air is between Carla Gericke and the Weare, N.H., police. She tried to film a traffic stop involving a friend in 2010 and was charged with breaking wiretapping laws. The charges were dropped, but she has sued the town and the police department. Her suit reached the US Court of Appeals. which sent it to US District Court for a jury trial.
Now, as the New Hampshire Union-Leader reports, Gericke must try to persuade a jury that she complied with police instructions amid the filming. The police contend that her behavior disrupted them in the line of duty. Who will the jury believe?
It's no surprise that with inconsistent behavior among the police with respect to filming, sites like Photography Is Not A Crime exist to reveal instances that might not otherwise be seen or heard of.
Just last week, after the filming of a New York police officer allegedly choking a man to death, the New York Police Department had to remind its officers of the law. As the New York Daily News reported, the NYPD sent out a memo that read, in part: "Members of the public are legally allowed to record police interactions."
The memo added: "Intentional interference such as blocking or obstructing cameras or ordering the person to cease constitutes censorship and also violates the First Amendment."
This reminder may also have been a response to a lawsuit asserting that on eight separate occasions, officers had arrested those who filmed them.
Now that the Missouri Highway Patrol has been put in charge of Ferguson by Gov. Jay Nixon, different principles and sensitivities might prevail.
In essence, though, once the police had threatened the media's rights to film them -- as opposed to targeting, as some do, citizen journalists -- their public standing was even shakier.