As the Republican primary field narrows, political pundits continue to talk about which "lane" of voters each presidential candidate fits into. Senator Ted Cruz hopes to target the evangelical and socially conservative lane, while Senator Marco Rubio and former Governor Jeb Bush continue to fight to the death for what is left of the so-called establishment lane. But with less than a week to go before the South Carolina primary, it is becoming increasingly clear that Donald Trump, like a massive truck careening down an interstate, is bound by no lane.

Republican primary voters in South Carolina historically vote for a candidate who "represents their hopes, their fears," rather than someone they think can win in the general election, says Katon Dawson, the former chairman of the state Republican Party. In order for a candidate to be successful in the first-in-the-south primary this Saturday, they need to speak to the "outrage from Republicans who have felt left behind by the last eight years of the current president," Dawson said.

That candidate right now is unequivocally Donald Trump. He has consistently been the frontrunner in South Carolina since this summer and his lead has only gotten wider since. A CBS News/YouGov poll from over the weekend shows Trump with a 42 percent lead compared to Cruz who is in second place at 20 percent.

What makes Trump's popularity in South Carolina all the more remarkable is that it is consistent across the state's entire spectrum of Republican voters. Unlike Iowa, where the Republican base leans evangelical, or New Hampshire, which is more libertarian, South Carolina is home to a uniquely diverse population of Republicans.

"Our electorate represents a microcosm of the Republican party nationally," says Joel Sawyer, a veteran South Carolina political strategist.

South Carolina is home to Tea Partiers, former members of the military, libertarians, moderates and everyone in between — and Trump is leading among nearly all of them. The only category of Republican voter that Cruz is beating Trump slightly in are those who identify as "very conservative," according to the CBS News/YouGov poll.

The other thing that sets South Carolina apart from Iowa and New Hampshire is the sheer numbers of Republican voters who are expected to turn up on Election Day. Seventy-four percent of Republicans said they "definitely" will vote this Saturday, according to the same CBS News/YouGov poll. In 2012, about 600,000 Republicans voted in the state's presidential primary. This year, Dawson expects about 700,000 voters to turn out. That's almost four times the approximately 180,000 Republicans who participated in the Iowa caucuses and more than double the 282,000 who voted in New Hampshire's primary.

The high levels of turnout expected on primary day largely comes from an increase in newly registered voters in the state, mainly from Republican districts. In South Carolina's 2008 primary there were 2.2 million registered voters, compared to 3 million in this election cycle, according to South Carolina newspaper the State.

The high voter turnout — especially among newly registered voters — expected in South Carolina's primary works in Trump's favor. He has already demonstrated that his campaign does better in a typical primary, like New Hampshire, in which more people participate, compared to a caucus state like Iowa, which requires a greater ground organization to get people out.

The increased voter participation in South Carolina mirrors the unprecedented level of national interest in this election. According to a survey by the Pew Research Center, 67 percent of the public describes the current presidential campaign as interesting. This is a significant increase from the same point during the 2012 and 2008 primaries where only 36 percent and 37 percent respectively, said the same thing.

Dawson says this heightened engagement in the election comes in part from the wall-to-wall media coverage of the race. "I have never seen this much earned media attention in 40 years of presidential elections," he remarked.

The other main driver behind the unprecedented attention being paid to this race is, of course, Trump himself. He is also its biggest beneficiary. Trump's success so far has been staked on generating enough media buzz to pull new voters out for him in droves, which appears to be working in South Carolina, as it did in New Hampshire.

But Trump still has several weak spots — many of which are self-inflicted — that could still make South Carolina voters pause on election day. The biggest one came during the latest Republican debate on Saturday, when Trump went after Jeb Bush by attacking his brother, former president George W. Bush, for the Iraq war and September 11th attacks.

"They lied. They said there were weapons of mass destruction and they knew there were none," Trump said during the debate. "The World Trade Center came down during your brother's reign, remember that," he yelled at Bush.

Trump's attack on George W. Bush was a gamble, considering how exceedingly popular the former president is in South Carolina, where voters "know him [and] they trust him," says Dawson. Not to mention that South Carolina is home to a sizeable population of former and active military members living on eight military bases.

In the days following the debate, Trump did not back down on his attacks on the elder Bush brother. During a press conference in South Carolina on Monday, conveniently scheduled on the same day that George W. Bush was joining his brother Jeb on the campaign trail for the first time, Trump doubled down.

"The worst attack ever in this country? It was during his presidency," Trump said on Monday, referring to the 9/11 terror attacks. Trump added that to say that George W. Bush kept America safe after 9/11 was like saying, "the [other] team scored 19 runs in the first inning, but after that, we played pretty well."

South Carolina Republicans might be a diverse bunch, but they are still largely socially conservative and those issues don't seem to be a priority for the Trump campaign. Other candidates, particularly Cruz, have ratcheted up attacks on Trump's positions on social issues leading up to the primary. During last Saturday's debate, Trump said Planned Parenthood "does do wonderful things having to do with women's health" just not related to abortion. Similar remarks are now featured prominently in a Cruz ad airing in South Carolina.

Conventional wisdom might suggest that Trump's willingness to repeatedly insult a beloved George W. Bush and praise Planned Parenthood a week before South Carolina's conservative primary might very well hurt him with some voters. But his double-digit lead over Cruz is sizeable enough that even if his comments do cause him to lose a couple of percentage points, he could still easily win the state. Then again, that assumes Trump's controversial statements damage him whatsoever with his supporters, which has yet to be the case.

What could ultimately end up hurting Trump in South Carolina the most is the same question that has hung over his campaign since the very beginning — whether all of his star power and poll numbers can actually translate into votes. Getting thousands of people to come to your rallies is one thing, but making sure people show up for you on Election Day requires a serious organizational structure of volunteers, field officers, and campaign veterans. Trump has invested very little in get out the vote operations in the early primary states, including South Carolina.

Cruz, on the other hand, has built up an impressive ground effort in South Carolina, with an army of campaign staffers and volunteers that have spent months making contact with voters across the state. Cruz is also aided by several cash-flush super PACs, who have taken it upon themselves to carry out much of the traditional work of campaigns on his behalf, like knocking on doors and distributing campaign literature. This impressive organizational effort could end up taking the wind out of Trump's sails when it comes time for voters to cast their ballots in South Carolina. A recent poll from a pro-Bush super PAC shows Cruz only trailing behind Trump by two points (although internal polls conducted on behalf of campaigns should always be taken with a large grain of salt). At the very least, it could be a much closer race than what appears in public polling.

The Democrats hold their primary in South Carolina a week after the Republicans, on February 27. Next up for the Republicans is Nevada on the 23rd, which will be an even bigger test for Trump than South Carolina, since it is a caucus. If Trump's get out the vote strategy remains unchanged in Nevada — that is to say, non-existent — he could very well wind up with the same outcome there as he did in Iowa, where he lost an early polling lead to come in second place.

"If you like politics," Dawson said, "this is about to be a fun week."