BOSTON (AP) — It’s the single most contentious element in the Patient Protection and Affordable Care Act of 2010 (PPACA): The requirement that nearly everyone have insurance or face a financial hit.

But in Massachusetts, the only state with a so-called individual mandate, the threat of a tax penalty has sparked little public outcry since the state’s landmark health care law was signed in 2006 by the governor, Mitt Romney.

Romney, now the presumptive Republican presidential nominee, pushed for the mandate saying it would discourage “free riders,” those who can afford health coverage but instead rely on emergency rooms for free care and drive up insurance premiums for everyone else.

“What we are mandating is that individuals have personal responsibility either to pay for their own health care bill or to receive insurance,” Romney said at the time.

As a presidential candidate, Romney has tried to draw a line between his law and President Obama’s, in most instances saying that states and not the federal government should decide whether to impose the requirement.

The Republican’s record as Massachusetts governor — specifically his economic and fiscal policies — has been thrust into the spotlight by Obama to argue that Romney’s prescriptions for an ailing nation are wrongheaded. Largely missing from that critique has been Romney’s record on health care. That’s probably because Romney’s health care plan provided a blueprint for PPACA.

Romney, who these days all but ignores the health care measure that was his signature achievement as governor even as he assails Obama’s, was vulnerable on the issue during the Republican primary race because conservatives largely are opposed to the mandate, arguing that it amounts to government overreach. It’s unclear how the issue will play in the general election as Romney seeks to woo voters across the political spectrum.