Gov. Chris Christie, R-N.J., seems to have learned from Rick Santorum's mistake in endorsing Mitt Romney in 2008, as Christie explained his support for Romney this year by pointing to the weakness of other Republicans rather than praising the candidate as an ideal conservative.

Christie told Morning Joe that he endorsed Romney "because of the people offering themselves from my party for president of the United States, it was clear to me that he was the best of the group and that he was the only one of the group that I thought gave us a good chance of beating the president."

Compare Christie's explanation to Santorum's praise for Romney in 2008, when he indicated Romney as "a conservative," someone "conservatives can trust" who would "fight  . . . for the soul of Republican Party." Santorum introduced those comments by summarizing his antecedent position of looking for an anti-McCain candidate, but he praised Romney as a candidate that conservatives could get excited about.

Romney made Santorum pay for that praise last night. "[F]our years ago you not only endorsed me, you went on Laura Ingraham and said, 'this is the guy who is really conservative and we can trust him.' Let's not forget that you said that," Romney said during the CNN debate.

Unlike Santorum, Christie offered an analysis of Romney framed only in "comparative" terms. Asked if Romney is "in trouble" if he loses Michigan, Christie answered in the negative. "No, because everything is comparative," Christie said. "Because, who's beating him in that group?" Continuing, he observed that "elections are about choice."

Christie is making the Romney endorsement that Santorum must now wish he had made.