Ramesh Ponnuru argues that Mitt Romney's interests coincide with those of Michele Bachmann. She would prevent Pawlenty or Daniels from consolidating the right-of-Romney vote (she would dominate the populist vote and Romney the establishment vote with Pawlenty and Daniels squeezed out) but have too narrow an appeal to win a nomination race against Romney. I think that is right if it comes to that, but I think there is another way to think about the divisions within the GOP primary electorate.
There are lots of axes dividing Republican primary voters. There are those who would not vote for either an economic or social liberal but who prioritize economic issues above social issues and vice versa. There are evangelical and non-evangelical voters. Ponnuru sets up the axis of establishment vs. populist. I think one very important axis dividing the GOP primary electorate is governance-oriented conservatism vs. subgroup affiliation-oriented conservatism.
On the one hand are voters who prioritize some kind of governing competence, electability and some minimum of ideological fidelity to what they imagine are conservative principles. On the other are voters who value the candidate's authenticity as a real conservative. It really isn't about ideology past a certain minimum (current pro-choicers and Obamacare supporters won't win over much of either group when push comes to shove.) A lot of it has to do with social group relations. Who do you show contempt for? Who shows contempt for you? For a certain fraction of voters, these questions are important markers of what side you are on. Or to put it another way: Alaska is not a right to work state and Alaska state workers are still unionized at the state level. Mitch Daniels ended collective bargaining for Indiana state government employees, slashed the size of the state employee workforce, and fought and won a series of education reforms that severely wounded the Indiana teacher unions. But if it came to a race between the two, some fraction of the Republican electorate would declare Palin the "real conservative" partly because Daniels didn't fight for right to work laws (he sacrificed that goal in the course of trying to get his education reforms through) and Palin was a principled and tough fighter for conservative goals. At this stage, whether you said Obama runs a gangster government works better for you (with a fraction of that electorate) than what you might have done to reform health care policy in your state. It isn't just the emotional satisfaction of seeing Obama and his media supporters assailed. The willingness to attack demonstrates the character that will be needed to take on the key issues of the day when times get tough in Washington. The contempt of the liberal media (especially if reciprocated) is a sign that they will never co-opt you. Pawlenty understands this dynamic. That is why he hollered about Obama's apologies and used a domestic violence metaphor in describing how Obama's agenda should be opposed.
Romney's main current challenge is not that Daniels or Pawlenty will consolidate the right-of-Romney and win enough centrist-leaning voters to beat Romney. It is that they will displace Romney among those voters who most value displays of governing competence and conservative accomplishment. When it comes to records as political executives, they both have him beat. Pawlenty and Daniels did not convert to being pro-life just before running for President. Daniels's social "truce" comment will hurt him (as it should), but he also signed Indiana's law defunding Planned Parenthood and defended it prudently. They both slashed government spending and balanced budgets, but neither signed an Obamacare-like health care bill. Daniels' record on reforming health care policy is far superior to Romney's. They also served two terms to Romney's one. When it comes to policy and ideological consistency, Daniels and Pawlenty are superior to Romney. In 2008, Romney could have argued that he was the candidate who best combined executive competence with ideological consistency (if you bought the makeover), but that was when his main opponents were Huckabee (often sounded too statist on economic issues) McCain (amnesty, the Bush tax cuts, and too much else), Giuliani ( where to begin..) and Fred Thompson (no executive experience.) Romney could claim either an experience or ideological advantage against any one of them.
Lacking the experience and ideological advantages of 2008, Romney will have to use his name recognition and war chest to prevent Pawlenty and Daniels from drawing away those voters looking for governing competence (well one definition of it anyway), conservatism, and electability.