Oh Mittens! he criticizes Santorum for what he himself did in 1992!!
Flash forward 13 years to February, 2007 and Romney offered a completely different rationale in an interview with ABC's George Stephanopoulos: "When there was no real contest in the Republican primary, Id vote in the Democrat primary, vote for the person who I thought would be the weakest opponent for the Republican."
http://www.dailykos.com/story/2012/01/27/1059049/-Mitt-Romney-offers-yet-another-explanation-for-why-he-voted-in-1992-Democratic-primary
Yet he lashes out at Santorum for his robo-calls urging Dems to vote for him the GOP primary:
Its a dirty trick. Its outrageous to see Rick Santorum team up with the Obama people and go out after the union labor in Detroit to try to get them to vote against me, Romney said on Fox & Friends on the day of the Michigan and Arizona primaries. Look, we dont want Democrats deciding who our nominees going to be, we want Republicans deciding who our nominees are going to be.
Read more: http://www.politico.com/news/stories/0212/73367.html#ixzz1ngoA6Y7l