But now, with Donald Trump's impeachment trial, congressional Republicans are willingly ceding their power to the President, and a deeply corrupt one at that.
They're willingly giving away the store while knowingly getting nothing in return.
Jonathan Bernstein at Bloomberg Media published an excellent piece on this point yesterday (link here or here) with the title "What’s Impeachable? Nothing, Republicans Seem to Say" and the deck title "Trump’s party has surrendered to the view that a president can do whatever he wants and needn’t submit to congressional oversight."
Here is the money quote: "It appears more and more that even if the House managers serving as the impeachment prosecutors are eventually allowed to call one or more witnesses, the trial will end after establishing the principles that the president may use the powers of the office any way he or she wishes to without constraint, and that presidents will no longer have any legal obligation to submit to congressional oversight."
To that end, Trump's impeachment trial is expected to wind down late tonight, unless witnesses are allowed. The President will almost certainly claim exoneration the moment a verdict is announced, a conclusion only a fool would believe.