Hard to gauge. But I won't be surprised if it all fizzles out. Truly major players typically use their power behind the scenes to get what they really want. Explosive testimony is usually the stuff of TV shows. On the other hand, Trump loves explosive stuff -- he finds that it typically benefits him: dissing McCain, being dissed by Cruz during the convention, accusations of misconduct by numerous women. Behind the scenes, he may very well have told Comey: go ahead, bring it on. You'll see just how quickly it spins to my benefit!