"functioning" democracy?? are you joking? do you know anything about campaign finance?

I know some bits about campaign finance, but I also know that most people I meet in the US care much more about physical security than they do about privacy/civil liberties/etc.. They vote for people who implement nasty policies and they do not make those votes because they have been tricked.

"Citizen are involved" and "the democracy is not function as intended and/or there is a situation that can not be rectified democratically" are anything but mutually exclusive.

Yes, true. It is also true that sometimes citizens knowingly choose nasty policies and then sleep soundly at night with those policies in place. Like you, I also do not approve of the way the US has changed, but I try to avoid tricking myself into believing that many US citizens feel the same way I do.

It may be a functioning democracy to whatever degree, but is it still a constitutional republic?

It isn't, as far as I can tell. But I think that happened a very long time ago, to great acclaim.