Who watches the watchers? It has to be us -- members of the public -- right?
That's why being able to record police officers -- with video or audio -- is so important to making sure our rights are protected.
In Illinois, however, there was a law on the books saying that audio recordings could not be made unless all parties consented. The ACLU of Illinois too the case to court and won on First Amendment grounds, as detailed in this Civil Liberties Minute podcast.
What about here in Montana?
The answer is the same here as it is everywhere in this country. You have a right to photograph that cop.