For sake of discussion, let's say Mueller runs the table on these fools, and basically proves Russian collusion all the way up to Trump... and Trump lets him do so without firing him... and just for maximum fun, somehow Pence was in on it too... Then let's say, that the consciences of the Republicans in Congress are shocked, SHOCKED I tells ya!, or conversely, the firing of Mueller is just such an outrage to them... either way their principles are so offended that they declare they have no choice but to impeach, remove etc...