Stephen Sondheim’s gut-punch of a musical, Assassins, has finally made it to Broadway more than a decade after its debut, and the reception has been largely positive. But audiences have been reluctant to reward the actors with the usual standing ovation, and Frank Rich thinks he knows why. “If the old maxim has it that you should never yell ‘Fire!’ in a crowded theater, it’s even worse to wave a gun in a crowded theater in New York City at a time when an Associated Press poll shows that two-thirds of Americans expect a terrorist attack before the election, with one-third expecting the political conventions to be a target.”