If/when the investigations into Trump look like they are going to result in prosecutions, we will see them also begin investigating Hillary in earnest.  The only way that Trump will go down is if they also take Hillary down as well.  They have been trying for 20 years to convict the Clintons of something, anything, but if it looks like Trump will be impeached, they will have to take Hillary down too, just to save face.  Hell, they still seem to be smarting over Nixon, and their failure to use Bill Clinton to take revenge on the Democrats over Nixon.