Six months ago, I warned that Donald Trump's strengths could also be the weaknesses that would destroy his campaign. I think we're beginning to see that play out now. Trump has repeatedly said he is a counterpuncher -- that he won't initiate attacks against his rivals but if they were to hit him first he would hit back much harder. He seems to take pride in this, as if it proves his toughness -- an essential part of the image he's cultivated. It's not just abstract machismo that he sells but muscularity in promoting the policy issues that form the...