The terrorist bombings in New York and New Jersey, which injured 29, and the terrorist stabbings in Minnesota, which injured nine, were nowhere near as serious as the terrorist shootings in Orlando, which killed 49, and in San Bernardino, which killed 14. Nevertheless, the acts of accused bomber Ahmad Khan Rahami, and of Dahir Adan, the stabber whose rampage was ended by an off-duty police officer in Minnesota, brought the issue of terrorism back to the presidential campaign trail.

There was a time when terror attacks were thought to benefit Trump politically, because polls suggested he was seen by many voters as tougher on the issue. But Trump is widely believed to have fumbled things badly after Orlando last June, forfeiting some of his advantage. New York, New Jersey, and Minnesota presented an unhappy opportunity to do better.