President Donald Trump averages about 16 tweets per weekend but was recently unusually active on the platform, posting more than 50 times from Friday morning to Sunday evening. He took on “Saturday Night Live” and the late Sen. John McCain and defended Fox News opinion hosts who have recently come under fire for bigoted statements. It was unclear what had provoked his flurry of activity, and even advisers were searching for the normal cues that set him off: White House officials performing poorly on the Sunday show circuit or his delayed distillation of negative coverage from the week before.