My guess is that they were SO CERTAIN that Trump was going to be removed from office that the nation would be so grateful that it would award POTUS to Hillary Clinton. That would atone for Trump stealing the election from her in the first place. AND they were going to give Hillary Trump's first three years as a replay / redo plus another eight years just because she deserved it. She wouldn't face the electorate for eleven years and, by that time, they would have gotten rid of the Electoral College so New York and California could re-elect Hillary through her 100th birthday.
Their plans went awry when impeachment blew up in their faces.
That's my theory and I'm sticking to it.
I like it.