But the trend of the last few weeks favors Chris Christie. The 2012 election has already proved to be a vicious, negative slugfest. In the last few weeks, Romney has been accused of committing a felony, avoiding taxes for a decade and contributing to the death of a woman with cancer. The squeals of various fact-checking outfits go ignored in Chicago. Romney, his family and staff are likely to feel offended and aggrieved. The question they are probably asking themselves is not: Who is the best vice presidential pick? Rather, it is: Who is the best wartime vice presidential pick?

Romney needs more than an appealing spokesman. He needs someone to engage aggressively on his behalf in the daily D-Day this campaign has become. All four leading vice presidential prospects might play this role. Christie would clearly play it best. He is the only one who seems to relish this sort of political conflict. And he has good reason to relish it. He is a natural, a prodigy, at the art of confrontation.