Rick Santorum used the first day of the Supreme Court's health law hearings to paint a distinction between himself and Mitt Romney on the issue of health care reform, saying the former Massachusetts governor knows he can't fight Barack Obama on the issue.

"There is one candidate who is uniquely disqualified to make the case. The reason I'm here and he's not," Santorum said of Romney as he spoke to reporters outside the Supreme Court. " The reason that I talk about Obamacare and its impact on the economy and on fundamental freedoms and Mitt Romney doesn't is because he can't because he supported government run health care as governor of Massachusetts."

Romney has promised to work as president to repeal Obamacare at the national level even though he enacted a state heatlh reform bill that is a model Democrats used for the national law.

In his stump speech, Santorum consistently links the healthcare plans of Romney and President Obama, even arguing Sunday night that Romney is the "worst Republican" for Republicans to nominate to run against Obama because of the similarities in the healthcare plans they proposed.

"Pick any other Republican in the country. He is the worst Republican in the country to put up against Barack Obama," said Santorum at a rally in Franksville, Wisc. Sunday evening.

Santorum's statement Sunday spurred questions from reporters asking he clarify his statement, which sparked an outburst from Santorum who yelled a profane comment at a New York Times reporter after the event.

"Quit distorting my words. If I see it. It's bullS@#$! C'mon man. What are you doing?" Santorum said to Jeff Zeleny of the New York Times.

"I don't regret taking on the New York Times reporter who was out of line," Santorum told reporters Monday afternoon at the Supreme Court.

But while he was peppered with questions about the incident, he tried to turn the attention back to the issue of the day arguing that Obama's healthcare plan is not constitutional and that healthcare is not a right.

"Rights should not, cannot, be created by a government because every time government creates a right, they can take that right away, and they can force you, as you've seen with Obamacare, they can force you to do something that are against what you believe is right for you and your family. They can do things that you believe are against the tenets and teachings of your faith, and that's not what rights are all about."

Hundreds of protestors listened on at the Supreme Court with some chanting phrases such as "Health care is a right" and "The ACA is here to stay."

ABC News' John Parkinson, Matt Negrin and Matt Larotonda contributed to this report.