I knew Jack Danforth when he was a U.S. Senator. When he is compelled to write something like this it is worth paying attention to.
To my fellow Republicans: We cannot allow Donald Trump to redefine the Republican Party. That is what he is doing, as long as we give the impression by our silence that his words are our words and his actions are our actions. We cannot allow that impression to go unchallenged.
As has been true since our beginning, we Republicans are the party of Lincoln, the party of the Union. We believe in our founding principle. We are proud of our illustrious history. We believe that we are an essential part of present-day American politics. Our country needs a responsibly conservative party. But our party has been corrupted by this hateful man, and it is now in peril.
Source: The real reason Trump is not a Republican – The Washington Post