Mitt Romney isn’t a naturally eloquent man. His stump speeches are nearly content-free. They combine exaggerated denunciations of President Barack Obama (“a pessimistic president,” “the great complainer”) and ardent professions of patriotism. “I love our country,” Romney announces at every stop. “I love our national anthem. ... I love it dearly. I love putting my hand over my heart.” He often closes speeches by reciting lines from “America the Beautiful.”

When he claimed victory in Iowa on Jan. 3, his syntax crumbled into Sarah Palin-like fragments. “We are an opportunity land,” he said. “People came from all over the world seeking freedom electorally, but also freedom personally, able to choose their own course in life.”

So it was noteworthy last week that when Romney addressed supporters after his New Hampshire win, he got serious and gave an actual speech, which he read from a teleprompter — a device he once mocked Obama for using.

It was a good speech, as campaign speeches go, especially when compared with the rest of this year’s lackluster oratory. And it was an important speech because it forced Romney to boil down the case for his candidacy.

His case? That he is a rock-solid conservative, not the closet moderate that some voters dread and others hope for. And that means the speech, for all its punch, held the germ of the main problem Romney will need to solve if he becomes his party’s nominee: Can he win votes in the center if he continues running to the right?

In his speech, Romney made it clear that he now considers himself running against Obama rather than the rest of the Republican field. He excoriated Obama for the disappointments of the last three years, calling him “a failed president.” And he reaffirmed his party’s core doctrine that smaller government is better government.

But then Romney went further. His campaign isn’t aimed merely at shrinking the federal government, he said, “It is about saving the soul of America” and restoring “America to the founding principles that made this country great.

“This president takes his inspiration from the capitals of Europe; we look to the cities and small towns of America.”

Talk about playing to the tea party. Romney’s theme — and it was far more extended than I’m reproducing here — was a barely veiled evocation of the old charge that the president isn’t a real American.

But it does raise a question. Is Obama modeling his policies on European principles? Hardly. His fiscal approach of continued stimulus is actually the opposite of Europe’s prevailing austerity policy. On Obama’s central domestic policy effort, universal health care, he looked not toward Europe but to Romney’s own state of Massachusetts.

More to the point, though, most voters outside the Republican Party base don’t really think Obama is a closet European — or a gloomy pessimist, for that matter. The patriotism gap Romney is trying to create is a device to mobilize tea party votes, not an appeal to the center. But as Republican red meat goes, it wasn’t bad.

And there was more. “President Obama wants to put free enterprise on trial,” Romney said. “In the last few days, we have seen some desperate Republicans join forces with him.”

Such finger-pointing, he said, is simply “the bitter politics of envy,” and he promised that “I will offer the American ideals of economic freedom a clear and unapologetic defense.”

In case that wasn’t clear, Romney escalated the argument in an interview on NBC on Wednesday, charging that the debate about income inequality is divisive and unpatriotic.

“I think it’s about envy. I think it’s about class warfare. When you have a president encouraging the idea of dividing America based on 99 percent versus 1 percent, and those people who have been most successful will be in the 1 percent ... (that) is entirely inconsistent with the concept of one nation under God.”

And here Romney, under pressure of the bitter politics of his primary campaign, has given Obama an opening to exploit. Most Americans are, in fact, worried about the declining incomes of the middle class, and a solid majority favor raising taxes on “millionaires and billionaires,” to use Obama’s deliberately divisive phrase. If Romney wages a campaign that focuses on defending the top 1 percent against the worries of the rest, he’s leading with his chin.

Romney did stand up for the middle class last fall, when he defended his relatively moderate proposal to abolish capital gains taxes for households earning less than $200,000 a year (instead of for all households, as most of his rivals for the nomination prefer). “I want to focus on where the people are hurting the most, and that’s the middle class,” Romney said then. “The people in the middle, the hardworking Americans, are the people who need a break.” But now his rivals’ attacks on his record as a venture capitalist appear to have pushed him further to the right.

Romney, like every Republican, wants to make the election a referendum on Obama’s record, a contest the GOP could win depending on the state of the economy this fall. Instead, he is giving Obama a chance to turn the election into a referendum on what kind of free-enterprise system the nation wants — one with regulations or without. That’s a contest the Democrats would find easier to wage.

Romney was once a Republican version of a centrist; he’s refashioned himself, doggedly, into a real conservative. But all the vitriolic rhetoric raises a big question: Will any voters in the center be able to convince themselves that he’s still a closet moderate? Romney, and the GOP, have to hope so, but their own campaign is making the task harder, not easier.

• McManus is a columnist for The Los Angeles Times.