Noah Millman doubts the importance of the Romney-Santorum contest:

The more I think about it, the less I feel like this primary season actually matters at all. Santorum’s insurgency has been compared to Goldwater in 1964, Hart in 1984, Jackson in 1988 – but these campaigns all reflected real and substantial disagreements about where the party should go, substantively, with different factions lined up behind the alternative candidates. But the more I watch this race, the less I see that kind of dynamic. There are cultural, geographic and demographic divisions between the two candidates’ bases of support. And there are obviously a whole lot of people who just don’t particularly want to vote for Mitt Romney. But I don’t see a battle for the soul of the party. I see a battle between two guys who want to be President.

There is some degree of factionalism in the divisions Noah mentions, but on the whole this seems right. He goes on to say that the nominating contest will continue, because ending it isn’t important. That could be, but I can’t recall the last time that a nominating contest dragged on for so long when so little was at stake in terms of the party’s direction or the content of its policies. It is also unusual for the out-party to consume itself with a long nomination battle in which so little is at stake when it has to challenge a sitting President in the fall. Insurgents typically want their party to offer “a choice, not an echo,” and Santorum has used similar rhetoric, but he is simply isn’t different enough from Romney c. 2012. Factional and cause-driven candidates have more incentive to drag out the process and maximize their influence inside the party. Reagan challenged Ford in an attempt to imitate Goldwater, he continued his campaign until the convention, and he very nearly won the nomination then, but that contest represented two significantly different visions for the party. Santorum and Romney represent more or less the same parts of the old Bush-era vision (they have kept the insolvency and imperialism, but reject Bush’s position on immigration).

The real difference between Santorum and Romney is one of style and personality: the dour crusader vs. the chameleon manager. Movement conservatives tend to be more attracted to Santorum because he is more ideological and has a longer record as “one of them,” but they would mostly search in vain for significant policy differences between him and Romney right now. Romney had to reinvent himself to turn himself into the Bush-era Republican that Santorum already was, but at this point there are not many sharp contrasts between them. Santorum’s insurgency is hampered in no small part by his record during the Bush era. Had he been less of a “team player” in the Senate, he would have fewer compromising votes that Romney could use against him now, and there might be some meaningful difference between nominating Santorum and Romney. As it is, there isn’t any, and the two arguably have fewer substantive differences on policy than Obama and Clinton, who didn’t have very many.