You are right, US is not there where UK already is. But unless people (and I don't mean 0.001% that hangs out on HN and like, I mean 99.999% that don't know what it is but vote) take serious interest in privacy and limiting government powers, we're moving in this direction, and moving there pretty fast. The fact that we have a president with which about 90% of the press are in deep and unquestioning love doesn't help either.

The "letter" of the law means nothing if the citizens are not ready to defend it. The congress can pass new laws, and as long as SCOTUS is ready to allow it - and experience teaches us when it comes to surveillance SCOTUS is ready to give a lot of allowances to the government - there's nothing to stop them but the citizens themselves. But if the citizens are more interested in voting in more government handouts for themselves than in liberty, then there's nobody else to stop it.