If Mitt Romney wants to win the Republican nomination for president this year — and he clearly does — he has one big hurdle to overcome, and it has to do with his anger. Or rather, the lack of it.

During the final debate before the Florida primary, the former Pennsylvania senator, and actual winner of the Iowa caucus, Rick Santorum took the opportunity to show some contrast between himself, frontrunner Romney, and former Speaker of the House Newt Gingrich. He homed in, as he had in the previous Florida debate, on the health-care plan Romney had shepherded into law while governor of Massachusetts.

Mitt Romney stunned me into Twitter silence when he responded to Santorum: “It’s not worth getting angry about.”

In a week during which one of Romney’s surrogates, former Minnesota senator Norm Coleman, suggested that President’s Obama’s signature health-care legislation couldn’t be overturned “in its entirety” — Republicans “can’t whole-cloth throw it out,” he added — it wasn’t the best answer. For conservative voters who don’t trust Mitt Romney, period, and trust him even less on health care, it wasn’t the best answer. It wasn’t the best answer, because Santorum’s point was that a government approach to health-care reform isn’t the best one, and that the discussion of health-care reform has to start from a position of freedom, not mandates. And it wasn’t the best answer, because our political scene has been transformed by the Tea Party, this new grassroots movement energizing voters who weren’t previously engaged in politics, and these activists are angry.

It wasn’t the best answer, either, because in the coming weeks and months, I predict, you will see a whole new level of engagement from religious Americans who are concerned about their loss of freedom in the intersection of religious belief and health care. The Obama administration has made clear that its reading of the Patient Protection and Affordable Care Act mandates that taxpayer money fund contraceptives, sterilization, and some drugs that may work as abortifacients. Further, if you are a religious organization that opposes such things, you will be forced to provide them in your employee health-care plans regardless.

The rhetoric this campaign season has suggested that radical religious-conservative Republicans want to take away your personal choice to use birth control. To the contrary: It is the radical Obama administration that insists that these things are a part of basic health care — and make no mistake, these ideologues believe abortion itself is, and they’ll force the issue as soon as they see an opening — and that you have no conscience right to keep your money or your religious institution away from them.

In the 2010 midterm elections that made John Boehner Speaker of the House, a TV ad ran that said: “There’s mourning in America.” Touching the economy, the family, and freedom itself, the spot described the disquiet in the country, and the buyer’s remorse that some of those who voted for Barack Obama were feeling. A lot of what Rick Santorum was getting at was captured in the line, “Our government is now taking over the choices we once made in life.”

That ad was a twist on Reagan’s famous 1984 “Better, Prouder, Stronger,” which declared that it was “morning again in America” as a result of Reagan’s leadership in the Oval Office. The creator of that ad, Fred Davis, explained the thinking behind it: “When everyone else is shouting, the most effective form of communication can be a whisper.”

Fifteen months after those 2010 midterms, people are more, not less, worried. They are worried about the economy. About the freedoms they were raised to cherish. About the very future of America.

Mitt Romney is wise not to join the Occupy screamers, campaign-rally hecklers, and talking-head interrupters. Yet, there is clearly something about Gingrich that resonates with voters, beyond his entertainment value. Could it be, perhaps, that Newt seems to embody an impatience and a sense of immediacy that voters across the board are feeling?

When Mitt Romney quotes lyrics from patriotic songs, recalling his cross-country trips with his parents as a youngster in their Rambler, this is what he’s actually trying to relay: a broad conservatism, based on a desire to preserve the country of his youth — the country he was raised to love. Romney seems keenly aware that America will not inevitably last, unless people are willing to fight for it in both principle and policy.

But an understandably skeptical voting public needs more than just latent awareness. And Romney hurts himself — and shortchanges his experience and his message — when he throws out a line like “It’s not worth getting angry about.” Because people are disappointed and hurting and, yes, angry. They are angry about a government that would mandate things that it has no business mandating. They are angry about a government that would force them to violate their consciences.

And they are worried. They wonder: “Once the government gets its way on this, what’s next?” Mitt Romney doesn’t have to — and shouldn’t — raise his voice or bully anybody. He certainly doesn’t have to become Mad Mitt. But he does have to demonstrate not only that he understands the concerns that Rick Santorum voiced, but that he can unite Americans by articulating that which is best about this land we all love: her freedom.

— Kathryn Jean Lopez is the editor-at-large of National Review Online. This column is available exclusively through United Media.