If the four GOP candidates were running for legislator-in-chief, Rick Santorum would have won last Wednesday’s debate. But they are not, and, coming off three caucus and one primary victories plus a surge in the polls, former Pennsylvania Senator Santorum failed to present himself as commander-in-chief.

He got mired in the arcana of Senate rules and legislative deal making to explain votes he had made. In a Tea Party era, where compromise is anathema, his willingness to “take one for the team,” which he did in voting for No Child Left Behind, is not unattractive. But his efforts to differentiate “good earmarks” from “bad earmarks” got him deeper in the legislative soup. Such explainers don’t play when the office sought depends on executive leadership. His contorted explanation of his support for Title X funding reminded me of John Kerry’s having voting for a bill before voting against it.

There’s a legislative logic to both, but hard to convey in a presidential debate format that demands simpler explanations.

Santorum’s best moment came when he attacked Mitt Romney for taking credit for balancing four budgets in Massachusetts, when that is required by state Constitution. Santorum got off the best line of the evening by noting that Mike Dukakis had balanced 12 budgets in Massachusetts, but that, he asserted, doesn’t make Dukakis qualified to be President. Surprisingly, Santorum failed to focus on Romney’s many flip-flops (or evolving positions), which are the heart of his vulnerability.

Romney came prepared to reassert himself as front-runner. His delivery was crisp, “fact packed,” and he seemed to have toned down his glassy, disingenuous smile. But the New York Times had a field day fact-checking Romney’s erroneous assertions, which he nevertheless delivered with aplomb.

It was the mostly affable elder statesman version of Newt Gingrich who showed up last night, rather than the angry, nasty individual who erupted, especially against the “liberal elite media,” in earlier debates. He did slip in one despicable remark about Obama and infanticide.  Overall, however, it was a low impact night for Newt.

Ron Paul was not even part of the debate for the first 15 minutes, occasionally got off a crowd-pleasing one liner, but is largely irrelevant, except as Romney’s corner man in attacking Santorum.

CNN’s John King never mentioned the word housing, despite the severity of the crisis in Arizona.  Local voters might have wanted to hear where the candidates stood on that.

Tuesday’s results in Michigan and Arizona will show to what extent Romney’s performance – plus his lavish spending – will succeed in regaining his path toward inevitable nomination. It’s all very unexciting. He approaches the primary process as a problem-solving businessman. His passion is unconvincing. In their excellent book, The Real Romney, Globe writers Scott Helman and Michael Kranish are thorough in probing what makes him tick. It’s well worth the read, a complement to what has unfolded in the debates, the last scheduled one having been last night’s. The last chapter has yet to be written.

I’d greatly appreciate your thoughts in the comments section below.