What Democrats would have to have is a majority in the House and the Senate and a President who will not veto what they send there — which presumably would be any Democrat. Even then, how ‘progressive’ would those bodies be?
Of course, given the Republicans’ absolute, unrepentant obstructionism, they would have to have 60 Senators. Short of that, unless the so-called ‘moderate’ Republicans (who sometimes say the right thing but never do it) were to grow a spine, they could accomplish nothing positive legislatively, regardless.
So the question becomes, should they stick with the Constitution or elect whoever would be more forceful in using the powers Trump has (ab)used?