New Hampshire’s presidential primary may be the news of the day but talk to any Republican strategist and it’s clear that the Granite State vote is only the appetizer to South Carolina’s main course in 11 days.

Republican presidential candidate, former Massachusetts Gov. Mitt Romney, campaign with South Carolina Gov. Nikki Haley, center, and Sen. Kelly Ayotte, R-N.H., at Pinkerton Academy in Derry, N.H., Saturday, Jan. 7, 2012. (AP Photo/Charles Dharapak)

Put simply: The Republican primary race will come to a fork in the road in South Carolina. A win by former Massachusetts governor Mitt Romney in the Palmetto State effectively ends the GOP nomination fight. A loss by Romney likely means a protracted primary fight that continues through Super Tuesday on March 6.

Conversations with South Carolina Republican strategists — and there are lots and lots of them (the Palmetto State may have more political consultants per capita than any other state in the union) — suggests the former path is the most likely at the moment.

“Romney wins unless something huge happens,” said one unaligned operative with deep experience in the state. “South Carolina is the first state that actually believes they are voting for a president and not electing a state party chair or sending a message. That attitude will significantly help Romney.”

The reality of the South Carolina vote, according to a number of well-informed GOP observers, is that it really amounts to two primaries in one.

In one primary is Romney — and to a MUCH lesser extent former Utah governor Jon Huntsman — who are competing for the establishment wing of the state’s GOP. These are voters who prize electability over all other factors and who gave Arizona Sen. John McCain 33 percent — and a win — in the 2008 South Carolina primary.

Romney is likely to win the lion’s share of those voters whether he spends a dime or $10 million on his South Carolina campaign since, unlike in 2008, he is clearly regarded by the smart set within the GOP as the most electable of the current field. (For why Huntsman isn’t likely to be a major figure in South Carolina, make sure to check out our post from this morning.)

That means Romney probably has a floor of about 30 percent in South Carolina and a ceiling around 35 percent almost no matter what he or his rivals do over the next 11 days.

The second primary is between former Pennsylvania senator Rick Santorum and former House Speaker Newt Gingrich — and, to a lesser extent, Texas Gov. Rick Perry. This primary is a fight for the mantle of consensus conservative candidate, a title that remains very much up for grabs at the moment.

The central dynamic of the race then is not then Romney versus Santorum/Gingrich/Perry but rather a three-way cage match — yes, the Fix was/is a huge pro wrestling fan — between Santorum vs Gingrich vs Perry.

(There is even a third primary within the primary and that one is where Texas Rep. Ron Paul resides. In South Carolina, Paul has a slightly smaller following than he has shown in Iowa and New Hampshire though they are no less dedicated. Polling suggests Paul is in low double digits at the moment in the Palmetto State.)

Romney wins in South Carolina if the race plays out along the same lines that the 2008 contest did in the state.

In that race, McCain easily won the establishment/electability primary and watched as former Arkansas governor Mike Huckabee and former Tennessee senator Fred Thompson split the conservative vote. Add the total votes of Huckabee and Thompson and you get 46 percent, easily enough to have defeated McCain if a consensus conservative had emerged. (Offered without comment: Thompson dropped from the race days after South Carolina and endorsed McCain.)

Romney loses South Carolina if either Santorum or Gingrich somehow emerges as the clear choice for conservatives between now and Jan. 21. For that to happen, it’s likely that either Santorum or Gingrich would have to implode in a major and high profile way — allowing the non-imploded candidate to make the case that he is the only option left to keep Romney from the nomination. (For Perry to emerge as that consensus candidate, he likely needs two implosions — a Spinal Tap drummer-esque scenario that is almost certain not to happen.)

Is it possible that conservatives coalesce with the prospect of Romney as nominee becoming more and more real? Sure. But remember that a consensus conservative is yet to emerge and Romney will, again, be the best funded candidate in the South Carolina race.