Supporters greet Donald Trump at a rally in Reno, Nevada on Sunday.AP Photo/Lance Iversen

Even as Donald Trump holds commanding leads in presidential polling, I’ve maintained that an establishment candidate still has the inside track to winning the nomination. As my Cook Political Report colleague David Wasserman outlined, the rules of the game are designed to favor the success of more-moderate candidates. If Trump or Ted Cruz wins the early-state contests, the proportional rules of allocating delegates will prevent either from running up the score. And the winner-take all rules for many of the more moderate “blue” states on March 15 and beyond should favor a more pragmatic Republican down the stretch—at least on paper.  

But these calculations are based on a premise that I’m having a bit more trouble accepting these days—that blue-state Republicans are more likely to support the establishment candidate than their red-state counterparts. It’s an especially shaky assumption to make with Trump, given the political pedigree of his strongest supporters. To put it another way, many of Trump’s supporters are self-described moderates and view him as the more centrist candidate. (Based on his history of holding liberal positions and past donations to prominent Democrats, they have a point.)

The ordinary rules of the political game haven’t applied to Trump so far, and if he lives up to the hype early on, there’s little reason to believe he’ll fade as the race moves into more moderate territory. If Trump wins Iowa—the one state where he hasn’t led in many public polls—it’s hard to see where his momentum stops. Such an outcome would prove that his supporters’ commitment is much more consequential than his lack of organization. He’d then be heavily favored to win New Hampshire, where he’s led throughout the campaign and where the establishment is badly splintered. He’d be well-positioned in South Carolina after that. With his populist, anti-immigration message resonating in the Deep South, it’s hard to see how he would fade as the primary season continues.   

The establishment’s best hope is that an alternative candidate emerges as Trump’s foil. This is where geography supposedly plays to that candidate’s advantage. On March 15, winner-take-all primaries will be held in Florida, Illinois, and Ohio. Wisconsin’s winner-take-all contest is on April 5, and a five-state Northeastern primary occurs three weeks later.

But even if the establishment field is narrowed down to one candidate by that point, it’s not a given that this candidate would beat Trump in a head-to-head matchup. As The New York Times’s Nate Cohn concluded, Trump’s strongest voters are “self-identified Republicans who nonetheless are registered as Democrats” and are well-represented in the industrial North and Appalachia. There’s a reason why Trump spent time last week in Lowell, Massachusetts and Burlington, Vermont—in two New England states that hold primaries on Super Tuesday. And polls show Trump’s favorability steadily improving among GOP voters, countering the widespread belief that he’ll flame out when the field narrows.

Trump is also performing adequately outside his base of white, working-class voters. In a divided field, he’s in first place at 21 percent among college-educated voters in New Hampshire, and he wins 17 percent of them in Iowa, according to the latest NBC/Wall Street Journal/Marist polls. He tallies 26 percent of the most affluent caucusgoers in Iowa, according to Quinnipiac. If he falters, it will be because these softer supporters would be the first to abandon him if he doesn’t live up to expectations. But if he achieves early success, the breadth of his current support should sustain him in more demographically diverse states. As it is, Trump is showing remarkable resilience in Florida polls despite running against two home-state icons in Jeb Bush and Marco Rubio.  

This is why the GOP establishment should be much more concerned about stopping Trump in Iowa than training its focus on Cruz. Cruz’s appeal is ideological, concentrated in the Deep South and states with high concentration of evangelical voters. He’ll struggle to consolidate support above the Mason-Dixon line, where his brand of conservatism isn’t as resonant. The path forward for an establishment candidate to take on Cruz is clear. By contrast, Trump’s supporters are more pragmatic—GOP voters of all ideological stripes view him as strong, economically fluent, and successful—and his appeal is more national.

Right now, Trump is like a buzzed-about public stock offering whose theoretical “value” is based on polling and the presumption of future success. There’s a reason he begins most campaign appearances by citing his first-place poll numbers.  

But it’s dicey to use polls to handicap this type of nomination fight. With Trump as the race’s defining figure, this is a race about momentum. Trump either has it, or he doesn’t. Iowa is a potential launching pad. If Trump wins the first-in-the-nation caucuses, he’s positioned to succeed across the primary map—in blue states and red ones. But if he disappoints in Iowa, his bubble is likely to burst.  

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