James Pethokoukis has a column pointing out that Mitt Romney's support for TARP is going to cost him support in a contested Republican primary. Likewise, Tim Noah had a terrific piece in Slate pointing out that Romney's health care position in Massachusetts was nearly identical to President Obama's. (Noah has a fun quiz mixing and matching Obama health care quotes with Romney health care quotes, and challenging readers to identify who said what.)
Romney is a useful marker in the frightening right-wing turn of his party. The GOP has been moving rightward for the last thirty years, but that shift has dramatically accelerated just since the fall of 2008. After Obama won the presidency, Republican officeholders and conservative pundits decided almost-unanimously was that the party's failure had stemmed from being too moderate.
The sudden ideological isolation of Romney is a case in point. During the 2008 GOP primary battle, he took a lot of heat for his former socially liberal positions. But his health care plan in Massachusetts attracted very little controversy. It was a classic moderate Republican plan, and one could very easily imagine Romney implementing something like it -- which is to say, something resembling the Obama plan -- had he won the presidency. Now it's seen as socialism, if not the end of American freedom. Likewise, the Bush administration and most Republicans favored TARP, but it, too, is now widely seen among Republicans as some dystopian attack on free enterprise ripped straight out of an Ayn Rand novel.
Romney's dilemma is compounded by the fact that he had to abandon some of his liberal social views to run for president in 2008. This gained him a reputation as a flip-flopper, which he's largely managed to put behind him, but he can hardly afford to do the same thing again this cycle. He's trapped with a 2008 issue profile running in a far more radical 2012 party. I think at this point it would take an enormous fluke for Romney to win the nomination. (Flukes do happen, of course -- see McCain's crazy path to the 2008 nomination -- but I consider Romney a decided longshot.)