J. Scott Applewhite / AP In one very important way, it is not at all surprising that Rob Portman has decided to end his long career on Capitol Hill after two terms in the Senate. He has been, for the most part, a mainstream Republican throughout his years in Congress – six terms in the House, and in his second term in the Senate. That's really not a happy place for a mainstreamer like Portman to be in these days. The heavy hand of Donald Trump still influences many of his colleagues and it has poisoned the well when it comes to reaching across the aisle and finding common ground with Democrats.