Is the United States finished as a free country?

Lately, I have seen a lot of people in my circles claim that the United States as a free country is dead and done, that tyranny advances each day and it's not isolated, it's everywhere. These are mostly reactions to articles reporting seeming home invasions by police, the FBI's forensic hair match scandal, and other government abuses. The common claim is that the United States now has an inherently corrupt justice system where policemen can end the lives of citizens with impunity and get away with it. My inner skeptic makes me feel that, while this is evidence of a lot of bad things that shouldn't be tolerated, the reaction itself seems disproportionate. While there are systemic problems, I have the impression that it is not all-pervasive and not hopeless. Then again, that could be also my inner optimist trying to tell myself that things are not as bad as they first appear. What is your take on the current climate of the United States? Do you think it is as finished as others claim it is? What kind of tools could you recommend for someone to use in gauging the state of the country more accurately?