There are some obvious similarities between Obama's health bill and Romney's in Massachusetts. Fundamentally, they are both based around the model of requiring people to purchase private insurance, with government subsidies for lower-income people. There are also some differences between the two, in terms of cost controls and how the programs are paid for. Another potential Republican presidential candidate, Minnesota Gov. Tim Pawlenty, has already criticized the Massachusetts plan in a veiled attack on Romney. And for his own part, Romney has vigorously attacked Obama over the issue.
Romney made a distinction, however, by saying that it should only be the states who launch these programs: "I like states being able to do what we did -- not the federal government." And he kept the door open to attempts to have the new law declared unconstitutional: "I can't say what the right judicial strategy should be, for trying to stop or slow down Obamacare, or reverse it, in key aspects."
Of course, it could be argued that this too is a change from Romney's position during his 2008 presidential campaign, when he specifically refused to back away from the idea of imposing mandates on a national basis: "No, no, I like mandates. The mandates work."