Defying the pleas of his own party brass, Rep. Todd Akin is refusing to abandon his campaign to unseat Democrat Sen. Claire McCaskill of Missouri. But is his quest for a Senate seat handing Democrats political ammunition to sink Republican hopes to win the keys to the White House?

Akin got into hot water for remarks aired in an interview Sunday, when he was asked whether he would support abortions for victims of rape.

In comments that instantly sparked an angry response from advocates, Democrats and even the ranks of his Republican party, the Missouri congressman replied that it was rare for women to become pregnant from a "legitimate" rape.

"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 told KTVI-TV in St. Louis.

Despite the howls of protest, and presumptive Republican presidential nominee Mitt Romney joining the ranks of those calling for him to abandon his campaign, Akin has said he has no intention of giving up.

He has since launched an ad campaign apologizing for his comments, and taken to the airwaves in his own defence.

"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."

Watching developments in Washington Wednesday morning, CNBC's chief correspondent in the capital said there's no reason to doubt Akin's commitment to his election bid.

"When he digs in and says ‘I'm going to stay in this race,’ you've got to listen to that -- at least until he changes his mind," John Harwood told CTV's Canada AM.

Conviction aside, the combined challenges of withering party support and raising the money to fund a campaign remains.

The Senate Republicans' campaign arm has already withdrawn $5 million in advertising planned for the Missouri race, and a major fundraiser has already been cancelled after the Senators slated to attend all pulled out.

The party has indicated Akin is cut off, Harwood said, suggesting that the long-time social conservative will have to turn to other sources for funding.

Akin has taken to social media, for example, asking for donations in an appeal that blamed the "liberal elite" rather than Republicans for pressuring him to quit the race.

In the meantime, his Democrat opponents are running with a prime opportunity to broaden their appeal among the women voters nationwide who helped President Barack Obama win his first term in the White House.

"The more you highlight attitudes like the one Akin expressed it's going to be harder for Republicans," Harwood said.

There is a close race for control of the U.S. Senate, which currently has 53 Democrats and 47 Senators.

Before this latest controversy, pundits and pollsters suggested the incumbent Democrat McCaskill was at risk of losing her seat. Whether that's changed now, Harwood said the race in Missouri has now taken on new significance.

Whether it tips the scales in favour of the Republicans regaining control of the Senate, or strengthens the Democrats' hold instead, the outcome of the Missouri vote "would be a critical factor for the president whether it's Mitt Romney or Obama," Harwood said.

Akin was among the supporters of "The No Taxpayer Funding for Abortion Act" introduced in 2011, the original version of which singled out "forcible rape" as the only case in which abortions for victims would receive federal funding.

Critics object to such language, because it suggests there are different severities of rape.

"People are disgusted and appalled," said Joe Mikosi, a Democratic congressional candidate in suburban Denver, who began tying his opponent, GOP Rep. Mike Coffman, to Akin within hours of learning about Akin's comments over the weekend.

It’s a strategy playing out in more than a dozen House races in battleground states, as Democrats employ the longtime political strategy of tying a controversy in one race to as many others as possible.

Whether painting Republicans as opposed to abortion even in cases of rape and incest is enough to win an election remains to be seen, Harwood said.

"We’ll have to see how that plays out."