Businessman Herman Cain’s acknowledgment earlier Tuesday that he is “reassessing” his presidential bid in the wake of allegations from Atlanta woman Ginger White that he engaged in 13-year extramarital affair looks very much like the end of his aspirations for national office.

CORAL SPRINGS, FL - FILE: Republican Presidential candidate Herman Cain speaks during a campaign rally outside of Wings Plus on November 16, 2011 in Coral Springs, Florida. (Photo by Joe Raedle/Getty Images)

And so, whether Cain decides to formally leave the race over the next few days or not, it’s clear now that his time as a top-tier candidate is over.

That reality prompts an obvious question: Who benefits from the Cain collapse?

The obvious answer is former House Speaker Newt Gingrich, who has been surging in recent days even as Cain has faltered.

Gingrich appears to be the latest in a long string of candidates — reality star Donald Trump, Minnesota Rep. Michele Bachmann, Texas Gov. Rick Perry and Cain — that have emerged as the conservative alternative to former Massachusetts governor Mitt Romney.

With Cain, Perry and Bachmann — all of whom continue to target social conservative voters — struggling, Gingrich can now reasonably make the case (and he has already started to do so) that he is the last conservative standing who has a real chance to unseat Romney as the nominee.

“I think it benefits Newt because it is in Romney’s interests to have the conservative vote as widely disbursed as possible,” said Rich Galen, former aide to Gingrich who is neutral in the current race.

Gingrich was, smartly, unwilling to speculate about the impact a Cain collapse — or a departure from the race — might have on him.

“This must be a painful period for him and his family,” said Gingrich during a campaign stop Tuesday in South Carolina. “He has to make the decision that he thinks is appropriate. I respect that he has to do that. That’s all I have to say.”

Another potential beneficiary from Cain’s repeated stumbles is Bachmann whose entire campaign continues to rest on her ability to make a strong showing in the Jan. 3 Iowa caucuses.

Bachmann’s victory in the Ames Straw Poll in mid-August seemed to cement her as the Iowa frontrunner but the rise of Perry — coupled with a series of senior staff departures — blunted her momentum in the state.

A recent Bloomberg News Iowa poll showed Bachmann at just five percent — well behind the likes of Romney, Cain and Gingrich.

But, Bachmann has been the most aggressive in calling out Cain over the allegations swirling — insisting that she is a no surprises candidate who conservatives can trust.

In a radio interview in Iowa today, Bachmann sounded that similar theme. “I’ve been the consistent conservative in the race and as people have been shopping around for the candidates I think they’re going to come back home and see I’ve been the consistent, constitutional conservative who’s going to fight,” she said. “I’ll be the strongest candidate to battle against I think Mitt Romney and Barack Obama.”

Bachmann’s problem is money, which she has struggled to raise since the dip in her fortunes over the last few months. If Bachmann doesn’t have the cash to cash in (ahem) on the Cain collapse, it’s possible that Perry, who remains well-funded if somewhat lost as a candidate, could fill that void.

While Gingrich and Bachmann seem to be the two most likely beneficiaries of Cain’s undoing, it’s also possible to make the case for how Romney could benefit too.

In a Pew poll conducted earlier this month, which showed Romney at 23 percent to Cain’s 22 percent and Gingrich’s 16 percent, Cain supporters split evenly between Romney and Gingrich when asked for their second choice.

This poll was in the field before the Gingrich surge began in earnest but still suggests that assuming that the entirety of Cain’s support will flood to the former Speaker is misguided.

Polling aside, there’s also the possibility that the Cain collapse convinces some portion of conservatives that no candidate in the field — up to and including Gingrich — can put together the full package needed to beat Romney, and that the former Massachusetts governor represents the party’s best (only?) chances to defeat President Obama next fall.

That realization could well push people — albeit is somewhat reluctantly— to Romney’s campaign.

Knowing exactly how the dominos will fall is impossible. But, if Cain does leave the race — or even if he stays in with much diminished support — it will send a series of ripples through the Republican candidate pool with just five weeks(!) remaining before the Iowa caucuses.