Amash has always voted with a strong Libertarian/Conservative bend and she, of all people, should know this (that's why I labeled her a disgruntled Trumper).
He read the Mueller report and came up with a different conclusion than AG Barr (as I did). He is a very principled person, I remember when Cruz was rock solid like that.
I'm not advocating for Impeachment but the Don Jr. emails alone show that there was an 'INTENT' to collude with the Russians to get hellarys emails 'Late summer would be great'. As far as obstruction I believe the case could be made for that too, IMHO.