What US agencies are in charge of counter-terrorism?

Answer 1

The Bureau of Counterterrorism and Countering Violent Extremism is part of the U.S. Department of State. It is responsible for coordinating strategies to defeat terrorism.

Answer 2

That's part of the problem; there isn't just one.

Department of Homeland Security is an enormously expensive department which is unable to focus on anything. DHS should take the lead, but doesn't.

Department of Justice wants to do something, but has no knowledge about how to prevent attacks by people who are willing to kill themselves in order to kill us, and lacks the will to actually DO anything.

For all that we've had three recent "consolidations" of our various and separate independent intelligence agencies, nobody talks to anybody else and it's all a monstrous game of "I've Got A Secret!".

There are too many politically correct barriers to action that nobody actually does anything except by accident. (For example, the easiest way to smuggle terrorists into the US would be to simply walk across the Mexican border - but we have virtually no border security there, because it would be perceived as "anti-latino". We actually have better security between the US and Canada than between the US and Mexico.