CNN
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The South Carolina Republican presidential primary is usually the most important contest of the nominating season. The state’s propensity for picking the eventual GOP nominee is unmatched by any other early-voting state. Since 1980, the only Republican to win the nomination without winning South Carolina was Mitt Romney in 2012.

This year, if history holds, it could mean the beginning of the end for Nikki Haley’s campaign.

Republican front-runner Donald Trump is dominating the polls. The former president has led every single poll in the state by at least 20 points this year. Surveys that meet CNN’s standards for publication have Trump up by at least 30 points this month.

To put that in perspective, I can’t find a single example of a well-polled presidential primary in the past 40 years in which a candidate has overcome the deficit Haley currently faces in her home state.

(Democrat Bernie Sanders’ 2016 Michigan primary win was the biggest recent shocker, and CNN approved surveys had him down by less than 20 points going into the election.)

Another ominous sign for Haley: Since the modern primary era began in 1972, no major-party nominee has ever lost his or her home state during the primary season. To that point, Trump has shown a knack for beating fellow Republicans in the states where they were first elected.

You may recall that Trump defeated Marco Rubio in the 2016 Florida primary, prompting the senator to drop out of the race. We’ll see if Haley ends up doing the same, though she has indicated otherwise.

While Haley is unlikely to take South Carolina, she is definitely outperforming her national baseline. Polls out this week from Marquette University Law School and Quinnipiac University have her losing to Trump by about 60 points on average nationwide.

Haley’s polling matches a historic pattern. Candidates usually outperform in their home states during the primary calendar. Candidates like Ted Cruz (Texas), John Kasich (Ohio) and Sanders (Vermont) all won their home-state primaries in either or both 2016 and 2020 but didn’t come particularly close to becoming their party’s nominee.

So the picture would likely only grow more dire for Haley after her home state votes.

Still, even if Trump does win Saturday’s primary (as every poll indicates), there are some questions pertaining to his scale of victory.

In 2016, Trump lost two counties on his way to winning the South Carolina primary: Charleston (home to the eponymously named coastal city) and Richland (home to the state capital of Columbia). A Trump sweep of both counties this time would likely mean he’d come away with all of the state’s delegates. South Carolina Republicans award 29 delegates to the statewide winner as well as three delegates to each winner of the state’s seven congressional districts.

Winning both counties would also indicate that any last resistance to Trump within the Republican electorate is fading. Both counties have relatively high levels of college graduates, who have been most hostile to the former president in GOP primaries historically.

Trump massively underperformed among college graduates in Iowa last month and outright lost them to Haley in New Hampshire. He got beaten by Haley among those with an advanced degree (e.g., a masters) in both Iowa and New Hampshire.

Trump winning college graduates in South Carolina would match what we’re seeing in national polling. Both Marquette and Quinnipiac put Trump at 60% of the vote or greater among college graduates (or White college graduates, in the case of Quinnipiac). Polling from the end of last year didn’t have Trump anywhere near that mark.

Indeed, if the polls are right about Trump, we will be left with one big question: Will he lose anywhere during the primaries?

Utah and Washington, DC, are the two places with primaries or caucuses on or before Super Tuesday where Trump performed the weakest in 2016. He got 14% of the vote in both places.

Victories there next month would all but guarantee Trump a milestone no other nonincumbent Republican has achieved in the modern presidential primary era: winning every single contest. This would leave little doubt that Trump is the heart of the GOP.