As has been made abundantly clear by his incessant mewling and pathetically thin skin, Donald J. Trump is not in fact an unwaveringly resolute tough guy of the type you would hope to find standing next to you in the trenches, but an insecure attention seeker who cannot help but pander to his audiences' prejudices. In the past few days, Trump has been asked variously whether, if elected, he would use his power to close mosques; whether he believes that Muslims should be registered in a special government database; and whether or not it would be a good idea to...