(Yahoo! News) -- President Barack Obama promised cheering supporters in Ohio that he would "make no apologies" for his overhaul of health care and mocked rival Mitt Romney's apparent change of heart on his own approach in Massachusetts.
"When you hear all these folks saying, 'Oh, no, no, this is a tax, this is a burden on middle-class families,' let me tell you, we know because the guy I'm running against tried this in Massachusetts and it's working just fine--even though now he denies it," Obama told about 300 supporters at Dobbins Elementary School in the village of Poland.
The president brought up health care often on this week's two day bus tour--the first of this election cycle. On Friday, the president's reelection campaign promoted an interview with an NBC affiliate in Cincinnati in which he hit Romney for changing his tune on whether the individual mandate—the requirement that people have health insurance—is a penalty or a tax. Romney says it's a tax in Obamacare but a penalty in his own plan.
"One of the things that you learn as president is that what you say matters and your principles matter," Obama scolded in the interview. "And sometimes, you've got to fight for things that you believe in and you can't just switch on a dime."
The debate has flared because the Supreme Court upheld Obama's signature domestic policy achievement under Congress's taxing power. Republicans have seized on that to accuse the president of breaking a pledge not to raise taxes on middle-class families.
The White House insists that the fine imposed is a penalty, not a tax."We're going to charge you a penalty to make sure that you're not unloading those costs on everybody else," Obama said in Poland. "It will affect less than 1 percent of the population, because most Americans are responsible and do the right thing. I make no apologies for it."
"We're going to keep it moving forward. It was the right thing to do two years ago, it's the right thing to do now, and we're going to keep moving," he said.