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SHELBY TOWNSHIP, Mich. - Mitt Romney attacked President Obama's "secular agenda" during a town hall in which he drew contrasts between himself and GOP rival Rick Santorum and defended his stance on conservative social issues for voters still making up their minds before next week's primary.

"You expect the president of the United States to be sensitive to that freedom and protect it and, unfortunately, perhaps because of the people the president hangs around with, and their agenda, their secular agenda, they have fought against religion," Romney said, responding to a question about religious freedoms, in particular the Obama administration's recent controversial attempt to require all institutions, including hospitals and colleges with religious affiliations, to offer free birth control and other contraceptives.

The policy was later rewritten to allow certain institutions to refuse to pay for the contraception and instead allow for private insurance to offer the cost of the coverage.

"I can assure you, as someone who has understood very personally the significance of religious tolerance and religious freedom and the right to one's own conscience, I will make sure that we never again attack religious liberty in the United States of America," Romney said, seemingly referring to his own Mormon faith, which has frequently been questioned during his various campaigns.

Romney, who was introduced by Michigan Attorney General Bill Schuette as "an underdog," spoke optimistically about his chances in his home state, telling reporters when asked about his state of mind, "Plan on winning, hope to win."

But not all audience members came to the town hall, held at fabrication company Eagle Manufacturer Corp., convinced that Romney is the one they'll vote for next Tuesday.

Feleiteau Epley, admitting that she had attended "the other fella's thing last week," in reference to one of Santorum's campaign events, asked Romney about abortion and gay marriage.

"I actually came in here undecided and I've been listening and everything is absolutely wonderful," Epley said. "One last question though will help me feel more comfortable. I just want to hear you say that you are 100 percent pro-life. … 100 percent no abortions … and 100 percent supporting marriage between one woman and one man."

"I am pro-life," Romney said flatly of his anti-abortion stance. "I am in favor of protecting the sanctity of life. I will cut off funding to Planned Parenthood. I'll reinstate the Mexico City policy. I'll make sure we appoint justices who follow the Constitution, don't stray from the Constitution to follow their own path."

Romney, 64, even invoked his pro-life position during an answer to a question about who might fill the vice presidential slot if he becomes the nominee.

"My vice presidential nominee will be pro-life," he said. "If I am fortunate to become the nominee ,I will also choose someone who is conservative to the core, who understands what it takes to make America strong again, and who is unquestionably an individual who can lead the nation if something were to happen to me."

Another woman in the audience asked Romney how he and his "campaign people" are going to "convince Michiganders in the next week that Rick Santorum is nothing but a Washington insider."

"I don't understand the surge," she added.

"Yeah, yeah, yeah. Well you make a good point," Romney said. "We have very different backgrounds. Sen. Santorum hasn't been as carefully viewed by the American public as have the others. We had Donald Trump for awhile and then we had Herman Cain and we had Rick Perry and Newt Gingrich. They have all been vetted pretty carefully. Rick Santorum is now just being seen for the first time in many homes and his background and mine are very different."

"The fact that he continues to defend earmarks including his $500,000 earmark to the Pittsburgh zoo for a polar bear exhibit. I don't think that is consistent with the principles of conservatism," Romney said. "I don't think Rick Santorum's track record is that of fiscal conservative."

This is Romney's first town hall event since Feb. 10, when he held a similar event in Maine. Town Hall events were commonplace in the weeks leading up to the New Hampshire primary but have been less frequent as the primary season has progressed.