(TheBlaze/AP) -- Rep. Todd Akin defied the nation's top Republicans Tuesday to forge ahead with his besieged Senate campaign, declaring that GOP leaders were overreacting by abandoning him because of comments that women's bodies can prevent pregnancies in cases of "legitimate rape."
Akin would now need to get a court order to pull out of the race as he waited beyond the 5 p.m. deadline, according to Missouri state law. The six-term congressman would also be required to shell out the cash for any necessary reprinting of ballots. If Akin were to leave, state law gives the Republican state committee two weeks to name a replacement.
Akin can withdraw from the race as late as Sept. 25 with a court order.
However, Akin has pledged to carry on with his quest to unseat Democrat Claire McCaskill. But his bid faces tall obstacles: a lack of money, a lack of party support and no assurance that his apologies would be enough to heal a self-inflicted political wound.
"I misspoke one word in one sentence on one day, and all of a sudden, overnight, everybody decides, `Well, Akin can't possibly win,'" he said on a national radio show hosted by former Republican presidential candidate Mike Huckabee. "Well, I don't agree with that."
Akin predicted he would bounce back from the political crisis threatening his campaign and capture a seat that is pivotal to Republican hopes of regaining control of the Senate.
"I'm in this race for the long haul, and we're going to win it," he told radio host Dana Loesch in St. Louis.
If he stays on the ballot, Akin will have to rebuild without any money from the national party and with new misgivings among rank-and-file Republican voters who just two weeks ago propelled him to a comfortable victory in a hotly contested three-way primary.
At several points during the interview with Huckabee, Akin focused on the idea he had misplaced a single word during a Sunday interview with St. Louis television station KTVI. But Akin has been roundly criticized both for using the phrase "legitimate rape" and saying a woman's body has the ability to prevent conception after such an attack.
Hours earlier, Akin posted an online video in which he apologized again for his remarks. Campaign spokesman Ryan Hite said the apology was intended to cover both the reference to "legitimate rape" and Akin's assertion that rape victims have a natural defense against pregnancy.
In a potential sign of his strategy, Akin appealed Tuesday to Christian evangelicals, anti-abortion activists and anti-establishment Republicans. He said he remains the best messenger to highlight respect for life and liberty that he contends are crumbling under the big-government policies of President Barack Obama.
As a key deadline to withdraw from the ballot loomed, Republican leaders intensified their pressure on Akin to exit.
Sen. Roy Blunt issued a joint statement Tuesday with all four of Missouri's living former Republican senators - John Ashcroft, Kit Bond, Jim Talent and John Danforth - saying "it serves the national interest" for Akin to step aside.
Pointing to the group, Republican presidential candidate Mitt Romney said the congressman should "accept their counsel."
A Romney aide said the candidate had been inclined to let Akin make the decision on his own. But after the Missouri lawmakers called for Akin to go, Romney wanted to make his position clear, said the aide, who requested anonymity because the aide was not authorized to publicly discuss Romney's thinking.
The deadline passed without any paperwork from the increasingly isolated Akin.
He provoked a political uproar when he was asked in the KTVI interview whether his general opposition to abortion extends to women who have been raped.
"It seems to me, first of all, from what I understand from doctors, that's really rare. If it's a legitimate rape, the female body has ways to try to shut that whole thing down," Akin said.
In the apology video posted Tuesday on YouTube, Akin acknowledged that rape can lead to pregnancy, adding: "The mistake I made was in the words I said, not in the heart I hold. I ask for your forgiveness."
The video will be running as a 30-second ad on TV stations statewide for several days, Hite said.
Here is his apology ad, titled "Forgiveness":