Lots of e-mails about how New Jersey’s Democrats will just dump Robert Menendez in the next few weeks for former interim Gov. Dick Codey — just as Bob Torricelli quit the race and allowed former Sen. Frank Lautenberg to waltz in. Sorry. Not gonna happen this time. Tom Kean is just too credible a candidate, far more palatable to New Jersey voters than Doug Forrester was in either of his last two races. You can play that switcheroo once. You can even play another game like resigning but delaying your resignation until after Election Day, as the sleazy McGreevey did in 2004. But that’s the limit. The Democrat who takes the nomination after a Menendez drop-out will be a state laughingstock, and under those circumstances, Kean will win in a landslide.