Are there like any issues where this dude would actually vote against party-line Republican positions or is this just about how much Trump sucks?
He actually had quite a history of voting with Dems in the state legislature before this according to the article the tweet linked:
A moderate Republican, McKean split with his party on many key votes in recent years, including the 2017 collective bargaining and workers compensation bills. He was the only Republican earlier this year to side with Democrats on an amendment to a proposed constitutional amendment on gun rights. He also joined Democrats last week in voting against a bill that allowed stun guns on college campuses. And McKean was the sole Republican to oppose the party’s push to change how the process of selecting judges in Iowa.