Editor's note: David Frum, a CNN contributor, was a special assistant to President George W. Bush from 2001 to 2002. He is the author of six books, including "Comeback: Conservatism That Can Win Again."
Washington (CNN) -- Mitt Romney ended a very bad week with a pretty good weekend.
Tuesday, Romney lost two caucuses and a nonbinding primary to Rick Santorum. Saturday, Romney won the also nonbinding Maine caucuses and the straw poll at the Conservative Political Action Conference.
Romney's front-runner status has been restored. But at what price?
Four weeks from now, no one will remember the Maine caucuses. I'm guessing though that people will remember a phrase from Romney's speech to CPAC on Friday, in which he described himself as a "severely conservative" governor of Massachusetts.
That phrase provides the Obama campaign with the second half of a potentially powerful negative ad. The first half is contained in this video clip from Romney's 2002 campaign for governor.
In the 2002 clip, Romney tells a reporter:
"I think people recognize that I'm not a partisan Republican, that I'm someone who is moderate, and my views are progressive."
In other words, on his way into the governorship, Romney promised moderation and progressivism. By his own telling in 2012, that's not what Romney delivered. Message: With Romney, you don't know what you're getting. You can't trust him.
By all accounts, the "severely conservative" phrase was a slip of the tongue. Romney intended to say "strongly conservative."
What was not a mistake -- what was carefully considered -- was Romney's other big appeal to conservatives this week. That was his decision to join the battle against the Obama administration's new contraception rule. Romney told Fox News on Thursday: "This effort with regard to contraception ... is an outrageous assault on religious conscience in this country."
The new rule would have required all employers to include contraception in their health plans subject only to very tightly defined religious exemptions. In practical terms, the Catholic Church would not be required to cover contraception for a secretary in a church office but would be required to cover a secretary working at a church-sponsored hospital. (On Friday, President Barack Obama said the rule would be changed to require that insurers, not religious institutions, provide the contraception coverage.)
The next day, Romney told attendees at the Conservative Political Action Conference that he acted to prevent Massachusetts from becoming "the Las Vegas of gay marriage" -- a throwback to his 2008 attempt to position himself as a social conservative and a deviation from his general practice in 2011-2012 of avoiding hot-button social issues.
It's been a pattern for Romney through this election cycle. Whenever Romney feels under pressure, he lurches right. We saw that pattern assert itself most recently in December, when Romney responded to Newt Gingrich's first surge by endorsing the Ryan budget plan, a step Romney had to that point resisted. Now in February, after losing Tuesday's three votes, Romney is debating contraception and gay rights.
Worse for him, the congressional Republican party has raised the ante, introducing in the Senate a bill that would allow any employer, religious or not, to deny contraception coverage.
These are not the issues Romney will want to discuss in the general election or the positions upon which he will want to be judged. But they are being forced upon him as the price of the nomination and he is acquiescing, to his and his party's future cost.
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The opinions expressed in this commentary are solely those of David Frum.