No one in the Republican party, given its current configuration, was entirely surprised when Donald Trump endorsed cardiac surgeon and daytime TV diet pill evangelist Mehmet Oz in the pivotal Pennsylvania Senate G.O.P. primary, on Friday evening, about five weeks in advance of the election. The nod, after all, was based on familiar Trumpian factors: going with the guy he knows best, the one who performs better on television, and who has done more to publicly tickle the erogenous zones of his ego. “He has lived with us through the screen and has always been popular, respected, and smart,” Trump wrote in his endorsement. “He even said that I was in extraordinary health, which made me like him even more.”