I’d argue that the GOPists have taken leave of their senses, but it’s really not so: They’ve taken leave of logic and legality. In a real trial (which this is not) “I was breaking the law in order to prove someone else was breaking the law” is not a proper defense. Of course, in a real impeachment, there would have been a large number of counts rather than just two. Someone pointed out elsewhere that this may be because the Dems didn’t want to impeach him for things they themselves do. Mebbe. But I’m inclined to think that their political calculation was more about what the right wingers might actually consider bad enough to convict… if they let themselves see it at all.