From his campaign website, here:
"The Romneycare individual mandate is essentially the same as the Obamacare individual mandate. Both reform laws rely on the government’s ability to tax and fine individuals to coerce them into purchasing “approved” health-insurance plans. Because of his support for an individual mandate, Mitt Romney finds himself at odds with the governors and attorneys general of 27 states, who are currently suing the federal government on the grounds that it is unconstitutional for the government to force people to purchase anything, even health insurance.
"Romney’s insistence that Romneycare is somehow different from Obamacare, simply because it was implemented at the state level rather than the federal level, is misleading. Romneycare, like Obamacare, is a massive intrusion of government into the private sphere. Neither of these government-run, top-down approaches to health care is the right prescription for America."
