Trump blew up the news-cycle yesterday by refusing to unequivocally say his campaign should call the FBI if it got an offer of oppo from a foreign power. The exchange was a little muddled — Trump at one point said he might contact the FBI as well as take the information, and he referred to a hypothetical involving Norway, while Stephanopoulos referred to Russia and China. The answer here is pretty obvious: If you are approached by a representative of a hostile foreign power, call the FBI. One reason for Trump’s stubbornness is clearly that he doesn’t want to throw Don Jr. under the bus and admit that he did anything wrong in 2016. But it’d be easy to say, “Don was new to politics and new to that kind of situation, but now, yes, of course we’d contact the FBI.” That Trump refuses to take the easy way out in such situations delights his hard-core supporters, but the cumulative effect of these unnecessary controversies is one reason he’s holding steady at 42 percent or so in the polls at a time of peace and prosperity.