My understanding from checking around the last day or two–after emerging from a semi-news blackout last week–is that Christie’s robust embrace of President Obama did break through and help President Obama rebut part of Romney’s closing argument that he can work across the aisle better than the president. Yesterday, the New York Post ran an editorial begging Christie to make a strong show of support for Romney. That kind of show of support might have been particularly important to Romney (and convenient for Christie) in the Philadelphia suburbs. But now it’s too late.UPDATE: Jon Ward reports on Christie turning down...