WASHINGTON -- Former Massachusetts Gov. Mitt Romney (R) is set to defend his state's health care law from conservative critics in a high-profile speech on Thursday. But Romney is far from being the potential 2012 Republican presidential contender with the most politically problematic record on health care.

That title likely belongs to former House Speaker Newt Gingrich (R-Ga.), who announced his White House aspirations a day prior to Romney's address.

In his post-congressional life, Gingrich has been a vocal champion for mandated insurance coverage -- the very provision of President Obama's health care legislation that the Republican Party now decries as fundamentally unconstitutional.

This mandate was hardly some little-discussed aspect of Gingrich's plan for health care reform. In the mid-2000s, he partnered with then-Sen. Hillary Clinton (D-N.Y.) to promote a centrist solution to fixing the nation's health care system. A July 22, 2005, Hotline article on one of the duo's events described the former speaker as endorsing not just state-based mandates (the linchpin of Romney's Massachusetts law) but "some federal mandates" as well. A New York Sun writeup of what appears to be the same event noted that "both politicians appeared to endorse proposals to require all individuals to have some form of health coverage."