Today, South Carolina voters will decide which of the Republican candidates they want as their presidential candidate come November -- and what seemed like a shoo-in for Romney a week ago, is now a horse race.

The surge of Newt Gingrich's chances after a couple of debates since being clobbered by Romney in New Hampshire, took something of a set-back thanks to an ABC network's interview with his ex-wife who claimed Newt wanted her to agree to an "open marriage" that would enable him to keep a mistress (whom he later married).

That Clinton-like scandal (which Newt exploited at the time when he was involved in similar antics) is unlikely to hurt Newt as much as it helps Rick Santorum among South Carolina's evangelicals. Family values, and all that.

Gingrich and Santorum (who did well in Thursday's debate) are in a struggle to depose Romney as front-runner -- which encourages the media to push the idea that a cliffhanger looms in today's vote.

This may be wishful-thinking.

The key question for most Republicans is which candidate is most likely to beat Barack Obama in November.

One result of tonight's vote (and Thursday's debate) seems the elimination of Ron Paul as a viable candidate. He was irrelevant -- a sideshow.

South Carolina polls shifted, once again, yesterday, following Thursday's debate which will be remembered mostly for Gingrich lambasting ABC's John King for raising his ex-wife's tirade against him. And Santorum's observation that the U.S. doesn't need a president who is erratic and unpredictable.

According to RealClearPolitics.com, Gingrich and Romney are in a virtual tie -- 32.5 per cent to 31.5 per cent respectively. Santorum (11.8 per cent) lags Paul (14 per cent), but no one is paying much attention to them at the moment -- especially Paul who seems out of it.

Until the two debates since New Hampshire, every indication was that Romney would win handily, despite Gingrich poor-mouthing him as a "Massachusetts moderate" and a "corporate raider" in business dealings.

South Carolina has blown hot and cold. In mid-December, polls averaged 41 per cent for Gingrich, 21 per cent for Romney. On Jan. 1, polls showed Gingrich at 37 per cent, Romney at 21 per cent.

Earlier this week, after Gingrich's campaign to slash and burn Romney was revved up a notch, SC polls showed Romney seven points ahead of Gingrich -- 29 per cent to 22 per cent.

So by his attempts to throw Romney under the bus, it's Gingrich who threw himself over the cliff -- until he excelled in the first debate after New Hampshire, and Romney couldn't effectively explain why his taxes were 15 per cent instead of 35 per cent.

After today in South Carolina, it's off to Florida for the Jan. 31 primary which is closed, with only registered Republicans voting -- a battleground state.

Even in Florida, the sands have shifted. In December Gingrich averaged 19 points ahead of Romney (43 per cent to 24 per cent), which on Jan. 1 had dropped to a seven point Gingrich lead (35 per cent to 28 per cent).

Today in Florida, Romney leads Gingrich by 18 points (40 per cent to 22 per cent).

So the GOP race is virtually decided -- if Romney wins today in South Carolina.

Then the choice for Republicans will be whether to unite behind Romney against Obama, or to view him as too moderate and stay home and enable the Democrats to win again.

Interestingly, polls show that although 49 per cent to 45 per cent of Americans disapprove of the job Obama is doing, still Obama is preferred over Romney by 1.9 per cent; over Gingrich by 11 per cent, Santorum by 9.5 per cent and Paul by five per cent.

Yet by a two-to-four point spread, Americans want a Republican to beat Obama in November. That may seem a contradiction, but it indicates both opportunity and obstacle for Republicans. And the campaign is only beginning.