Nominally the "check" on this would be impeachment-and-removal, I guess. In practice, given the current partisan environment and the very high vote requirement

Nominally the "check" on this would be impeachment-and-removal, I guess. In practice, given the current partisan environment and the very high vote requirement (2/3 of the Senate), I rather doubt it'll ever happen unless something even more ridiculously corrupt-looking than the current (quite corrupt-looking) news occurs...