Santorum said the president's plan doesn't resolve the issue. He says many Catholic institutions are self-insured and those organizations will still be forced to pay for women's contraception despite their religious objections.
"There's no compromise here. They are forcing religious organizations, either directly or indirectly to pay for something that they find is a deeply, morally, you know, wrong thing," Santorum, a Catholic, told NBC's "Meet the Press."
The focus on social issues plays well for Santorum, who has long been considered a staunch cultural conservative. Those credentials helped fuel his success last week.
But he wasn't a factor in Maine, where Romney captured 39 percent of the vote, narrowly defeating Paul's 36 percent, state Republican chairman Charlie Webster said. Santorum and Gingrich, who didn't actively campaign in Maine, won 18 percent and 6 percent respectively.
It was a disappointing showing for Paul, who on Sunday suggested that there was virtually no difference between his rivals.
"All three of them have represented the same system, the same status quo," Paul said on CBS' "Face the Nation."
The Maine vote totals reflected about 84 percent of the state's precincts, with nearly 5,600 Republicans voting out of 258,000 registered. The contests scheduled for the coming days will not be counted, including an entire county that postponed its caucuses because of a snow storm.
"We were a little bit disappointed last night," Paul said, because he's done well in that county in the past and expected to do well Saturday.
Coming off last week's success, Santorum saw a surge in donations. His campaign reports gathering $3 million in the three days immediately following after last week's hat trick, but he's unlikely to catch Romney in the money race.
Santorum reported just $279,000 in the bank at the end of December, compared with Romney's $19.9 million. Gingrich had $2.1 million, but is still carrying substantial debt, while Paul reported $1.9 million.
Romney won 11 delegates and Paul 10, according to an analysis of the Maine results by The Associated Press. Santorum and Gingrich were shut out. That brings the delegate count to 123 for Romney, 72 for Santorum, 32 for Gingrich and 19 for Paul, with 1,144 delegates needed for the nomination.
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