Santorum, a former U.S. senator from Pennsylvania, also caught some flak from conservatives who said they were bothered by Santorum's vote to approve the 2003 Medicare drug bill.
Santorum's support for the GOP's effort to enact a Medicare prescription drug benefit has been used by conservatives as evidence about government spending run amok during Republican President George W. Bush's two terms, The Hill reported Friday.
Santorum told CNN he "held his nose" while voting for the drug benefit "because we did have the private sector model for Medicare prescription drugs … ."
As the third-ranking Senate Republican when the GOP controlled Congress and the White House, Santorum urged colleagues to vote for the drug benefit, which was estimated at the time to cost nearly $400 billion over 10 years with no offsets.
Santorum since said he wished the bill had been paid for and even told Fox News his "yes" vote was a "mistake." However, conservative bloggers and other candidates say his vote indicates he is a liberal.
During College Convention 2012 in Concord, N.H., Thursday, Santorum didn't avoid questioning on his views concerning same-sex marriage, but asked that the discussion be civil, The Hill said.
Santorum has expressed support for a federal ban on same-sex marriage, which drew both boos and cheers from the crowd.
Santorum goes into New Hampshire's primary Tuesday with a second-place finish in the Iowa caucuses, just eight votes behind former Massachusetts Gov. Mitt Romney.
Santorum said he wasn't familiar with language of medical marijuana laws in various states but said he believed marijuana use was dangerous, based on his personal experience of seeing it used.