The Wall Street Journal published an especially withering assault on Romney’s plan in its op-ed pages on Thursday, calling him “compromised” and “not credible” on debating President Obama over healthcare.

Romney has defended his program by, among other things, invoking states' rights and making a distinction between plans imposed at the federal and state levels. In a Thursday speech at the University of Michigan, he offered his fullest defense yet of his policy and the politics surrounding it, claiming he wouldn’t back down from defending his plan, no matter the political cost.

“A lot of pundits around the nation are saying that I should just stand up and say, ‘This whole thing was a mistake’ ... and I presume that a lot of folks would conclude that if I did that, it would be good for me, politically. But there’s only problem with that: It wouldn’t be honest. I, in fact, did what I believed was right for the people of my state.”