The New Testament book of James compares the tongue to a small rudder that guides a huge ship. Rep. Todd Akin, R-Mo.-an evangelical Christian-might be thinking about that passage today.

In less than 48 hours, two words that Akin uttered during a television interview on Sunday have steered the course of his promising Senate ambitions to a potential shipwreck.

The two words: "legitimate rape." The context: a discussion of abortion.

Republican leaders now worry that Akin could lose his Senate race in Missouri against incumbent Democrat Claire McCaskill, and that the GOP could lose a chance to regain the Senate in November. Pressure is mounting on Akin to drop out of the race by 5 p.m. CDT today, even as he releases a campaign ad apologizing for his remarks.

Those remarks came when an interviewer asked Akin whether abortion should be legal in the case of rape. The six-term congressman said such a scenario is rare, adding that if it is "a legitimate rape, the female body has ways to try to shut that whole thing down."

The comment ignited an immediate firestorm. Akin later said he "misspoke" and that his remark "does not reflect the deep empathy I hold for the thousands of women who are raped and abused every year." He wrote on Twitter: "All of us understand that rape can result in pregnancy. …"

By Tuesday morning, Akin had taped a campaign ad to run statewide in Missouri, saying, "I used the wrong words in the wrong way and for that I apologize." Akin called rape "evil" and told viewers, "The mistake I made was in the words I said, not the heart I hold." (See video below.)

The apology hasn't swayed GOP leaders. Republican presidential candidate Mitt Romney called Akin's original comments "insulting, inexcusable, and, frankly, wrong." A Romney campaign statement said that "a Romney-Ryan administration would not oppose abortion in instances of rape."

That statement highlighted a difference between Romney and his running mate: Rep. Paul Ryan, R-Wis., has opposed abortion except when a mother's life is in danger.

Other pro-lifers have long opposed Romney's support for abortion in the case of rape. They've said what Akin could have said in response to the question on Sunday: The violent tragedy of rape does not justify the violent tragedy of abortion. (And victims need tremendous support to deal with the crushing burden of both rape and the resulting pregnancy.)

For now, GOP heavyweights like House Speaker John Boehner, Senate Republican leader Mitch McConnell, and Sen. John Cornyn of Texas have pressured Akin to drop his Senate bid by the end of the day. (After 5 p.m. CDT today, Missouri law says that Akin-or any other candidate-would have to get a court order to withdraw, since the race will be less than 11 weeks away.)

Democrats have pounced on the controversy, using the firestorm to defend broadly pro-abortion views. President Barack Obama said Akin's comments "underscore why a bunch of politicians … shouldn't be making decisions on behalf of women."

In a fundraising email, Democratic National Committee Chairwoman Debbie Wasserman Schultz said she was "outraged at the Republicans trying to take women back to the Dark Ages."

Meanwhile, at least two pro-life groups have offered support to Akin. The Washington, D.C.-based Family Research Council released a statement calling the controversy "gotcha politics," saying that Akin "has fought against forcing taxpayers to subsidize abortion giant Planned Parenthood, which is the bedrock of Claire McCaskill's base of support."

The pro-life Susan B. Anthony List released a statement saying Akin had been "an excellent partner in the fight for the unborn."

Indeed, Akin has a 100 percent voting record on pro-life issues according to National Right to Life and has been a staunch defender of pro-life legislation. The congressman-who earned a Masters of Divinity from Covenant Theological Seminary in St. Louis in 1984-has also served as a board member of the Missouri Right to Life.

Last year, the pro-life group Defenders of the Unborn announced that Akin would speak at an event celebrating the closing of a Missouri abortion clinic. The announcement identified Akin as a ruling elder at Twin Oaks Presbyterian Church (Presbyterian Church in America) in Ballwin, Mo. (Akin does not appear on the church's website as a current ruling elder serving in 2012.)

Akin's Senate endorsements include prominent pro-life supporters-like Eagle Forum leader Phyllis Schlafly and former Arkansas Gov. Mike Huckabee-as well as dozens of evangelical pastors.

But Akin's pro-life record may not be able to overcome his painful comments. Even if GOP leaders accept his apology-or believe he misspoke-they're unlikely to risk a Senate seat they think they can win without Akin.