"Replacing Lautenberg poses several problems for Christie."

"State law allows Christie to appoint a replacement, and maybe to hold a special election later this year. (It's possible, Politico explains, that because it's too late for a primary, an election might have to wait till 2014.)"

... "Rumors have abounded for months that Christie was considering appointing Cory Booker," Politico's Maggie Habermann and Ginger Gibson write. "However, sources close to both men have insisted this scenario makes no sense for either of them."

So, if Christie appoints a right-winger, he angers the Democrats he needs to be reelected. If he appoints a Democrat, which he probably won't, he infuriates the Republican base he would need in the 2016 Republican primary. But splitting the difference won't work, either. Salon's Steve Kornacki points out that appointing a non-controversial old Republican as a caretaker for the seat is not without risk.

Give Christie some advice.

I assume he wants to run for President in 2016. If so, he can't reinforce the suspicion that he's really a Democrat (unless he wants to do that Lincoln Chafee thing and become a Democrat). After hanging out at the shore with Obama a bit too much, he needs to send the message he's conservative, I would think.