In 2011, the First Circuit Court of Appeals out of Massachusetts ruled in favor of citizens first amendment rights to record in public. The Court has jurisdiction over MA, NH, RI, ME, and Puerto Rico.
Here's the ruling:
"[I]s there a constitutionally protected right to videotape police carrying out their duties in public? Basic First Amendment principles, along with case law from this and other circuits, answer that question unambiguously in the affirmative."
"Glik filmed the defendant police officers in the Boston Common, the oldest city park in the United States and the apotheosis of a public forum. In such traditional public spaces, the rights of the state to limit the exercise of First Amendment activity are 'sharply circumscribed.'"
"[A] citizen's right to film government officials, including law enforcement officers, in the discharge of their duties in a public space is a basic, vital, and well-established liberty safeguarded by the First Amendment."
"Gathering information about government officials in a form that can readily be disseminated to others serves a cardinal First Amendment interest in protecting and promoting 'the free discussion of governmental affairs.'"
Unfortunately many states and police departments continue to arrest people for filming. These arrests constitute an abuse of power and are completely unlawful and unconstitutional and, unfortunately again, it will probably take more arrests and more lawsuits by individuals before all 50 states allow citizens their 1st amendment rights to free speech and free press by recording their interactions with police and other public officials.
We encourage you to look up the law in your city or state but we also encourage you to not be afraid and to film any misdeeds in public that you may be witnessing. A free press begins with you!
"Individuals have international duties which transcend the national obligations of obedience...therefore individual citizens have the duty to violate domestic laws to prevent crimes against peace and humanity from occurring"
-- Nuremberg War Crime Tribunal, 1950