Today, the response would have to be at a whole other order of magnitude—an unprecedented shock to the system that would force those all but most Trump’s impassioned supporters to rethink the consequences of his nomination. It would involve a clear declaration by as many voices as possible that Trump would be unacceptable as a president, accompanied by a massive media campaign designed to undermine the core of his appeal. It would mean a frontal attack on his character and temperament—and a willingness to absorb all the blows he is brilliantly capable of launching. It’s not clear that they could even pull it off at this late date—and if you look at what the options really are, it’s not clear the party would avoid serious long-term damage if they did. But at this point, this implausible nuclear option is the only remotely plausible approach.