The founders seem to have imagined that Congress (as a whole) would have an adversarial relationship with the President. But they failed to foresee the levels of partisanship we have today which have resulted in ~half of Congress being very closely allied with the President.
When the US was less divided, things like ethics or morals or even just not openly breaking the law mattered a lot more. Now, people (at least, the people who vote the most) care more about "is my party in power", and either don't know about or disregard everything else. I include "don't know" because if all you listen to is Fox news and social networks feeding you ideas that you already agree with then you can easily be completely unaware of things like this.
There's just no one with the power plus willingness to do so.
The US is over.
(for some reason this attracted a downvote? Obviously Republicans are never going to impeach a Republican President? I cannot imagine why you would think they would?)