When the Klieg lights are turned on at the must-see debates next fall, though, don’t expect the candidates to tread on such common ground. Christie will look to smash what one Republican operative described as Booker’s “glass jaw” by attacking him for being the same kind of tax-and-spend Democrat that brought New Jersey the highest property taxes in the nation. He will say that Booker followed the playbook of his tarnished ally, former governor and bank boss Jon Corzine, by failing to address Newark’s structural deficit and continued reliance on suburban taxes. Like Democrats in Congress who ignore the cost of entitlements, Christie will argue, Booker failed to do the “big things.”

Christie’s been to war before as a federal prosecutor, challenger to Corzine, and chief surrogate for Romney. Booker won his mayorship in a nasty race against a longtime state senator, but he’s the relative newbie on the national scene. So he will first try to deflect Christie’s shots with some of the platitudes he peddles on Twitter. Failing that, he will follow the advice of the focus groups and attempt to exploit Christie’s gender gap by repeatedly bringing up the governor’s opposition to abortion and gay marriage. He will frame these as civil rights matters, then go for the gut by questioning Christie’s blue-collar-hero status—that the governor reduced a tax credit for the working poor, while vetoing taxes for millionaires.

Most of all, Booker will wait for the inevitable insult, some word that Christie lets slip that a few thousand independent voters think goes too far. This isn’t a state where we want our leaders calling lawmakers “numbnuts” and Navy SEALs “idiots,” as Christie has done. Booker will wait for that gaffe, and then let it simmer. The message: Christie’s tough talk, his Insult the Comic Dog routine, is growing too old, New Jersey. You’ve done bold; now is the time to go bald.