The Herman Cain train has officially derailed.

Cain, the Georgia businessman whose sudden rise in the polls in October shook up the Republican presidential field, announced in Atlanta on Saturday that he would withdraw from the race in light of allegations of a 13-year extramarital affair and several 1990s-era sexual harassment accusations.

It's time for solutions. But as false accusations about me continue, they have sidetracked and distracted my ability to present solutions to the American people, Cain said. Now, I have made mistakes in life. Everybody has. I've made mistakes professionally, personally, as a candidate in terms of how I run my campaign, and I take responsibility for the mistakes that I have made, and I have been the very first to own up to any mistakes that I've made.

But, he said, the false and unproved allegations have taken a toll on his family -- and so, with a lot of prayer and soul-searching, I am suspending my presidential campaign.

Cain said he would continue to push his proposals, such as his 9-9-9 tax plan, his foreign policy ideas and his energy independence plan, through a Web site called TheCainSolutions.com. He added that he would endorse another candidate soon.

For the past month, Cain had vowed to stay in the race in spite of the growing storm surrounding allegations that he sexually harassed several women when he was CEO of the National Restaurant Association in the late 1990s. He swore on multiple occasions that he would not be driven from the race by character assassination from people who, he claimed, fear a Cain presidency.

And if the allegations had stopped there, he probably would have stayed in the race, even if his poll numbers never recovered.

But on Tuesday, another woman, Ginger White, 46, came forward to allege that she had had a 13-year affair with Cain. She had some evidence to back up her claims -- phone bills showing more than 60 phone calls and text messages to and from Cain's personal cell phone -- and while Cain responded that he had only been helping her financially, not having sex with her, the public backlash was just too much for an already weakened campaign to overcome.

Even campaign officials had acknowledged that Cain's chances of winning the nomination were looking increasingly slim. A Des Moines Register poll released on Friday showed him with just 8 percent support in Iowa, which will hold the nation's first caucuses on Jan. 3, putting him well behind current front-runners Newt Gingrich and Mitt Romney. That's down from 23 percent support in the last Des Moines Register poll in late October, and Cain's Iowa campaign chairman, Steve Grubbs, said the new figures were in line with the results of the campaign's internal polling.