How Rubio can lose early primaries and still win

If Marco Rubio is the front-runner to win the Republican presidential nomination, as election prediction markets are saying (and I agree!), then why aren't his poll numbers spiking?

That's what the Rubio naysayers keep asking. No matter that the Florida senator just moved into second place, behind Donald Trump, in HuffPollster's national poll estimate. In addition, only 15 percent of Republican voters so far say they won't vote for him after carefully considering him.

Among the Rubio skeptics, Ed Kilgore at New York magazine has been raising a more thoughtful question: At what point in the primaries will Rubio start winning elections?

Kilgore is correct that factional social conservatives tend to prevail in the Iowa caucuses, which are on Feb. 1. This makes it more likely that Ben Carson, Ted Cruz or even Mike Huckabee or Rick Santorum will wind up first there.

New Hampshire votes on Feb. 9, and Trump has a large lead now. Chris Christie, Jeb Bush and John Kasich will throw everything they have at the state. Even if they fall short, they could hurt Rubio, who may be too conservative for New Hampshire's moderates. Meanwhile, Cruz is running hard in Southern states, and it isn't hard to imagine him winning in South Carolina, which votes on Feb. 20.

So how and where does Rubio win?

There are many possible scenarios.

One is that if he jumps 10 percentage points or more in the polls -- and any candidate can have a surge -- he's already in good enough shape that he'll probably win in Iowa and then perhaps in 40 or more states. Polling surges are mostly unpredictable, but Rubio has a lot going for him. He's a skilled debater, and he's on the main stage at these events. High- profile Republicans are moving to his column, which will magnify anything good that happens to him.

But what if he doesn't get that polling surge?

Mitt Romney didn't in 2012, yet was able to earn a tie in Iowa with 25 percent of the vote. An even lower total could win the caucuses this time if Cruz, Carson, Huckabee and Santorum split their vote more or less evenly, and if Trump either fades a bit (he's at about 26 percent in current polling there) or, as seems reasonably likely, many of those who support him in public opinion polls fail to turn out.

In New Hampshire, Trump's current poll lead is stronger. But if Cruz wins in Iowa, the Granite State's moderates may be eager to find a Stop Cruz candidate, and might be willing to switch to Rubio. Despite being more conservative than the Republican voters there, he would still be the logical choice if he remains ahead of Bush, Christie and Kasich in state polls and if he beats those three solidly in Iowa. Add in the lost luster for Trump if he fails to capture Iowa, and maybe Rubio squeaks over the finish line first in New Hampshire.

If Trump wins in Iowa and New Hampshire, or if a social conservative prevails in Iowa and Trump takes New Hampshire, could Rubio still take South Carolina? Yes, if Rubio has done well in the first two states. At least two and perhaps all three of Christie-Kasich-Bush will probably have left the race by then. If the ballot is only Trump, Rubio and one or two social conservatives (say, Cruz and Carson), then Rubio will likely do well with voters who supported John McCain in 2008, George W. Bush in 2000 and Bob Dole in 1996.

Even if Rubio fails to win any of the first states, he could still be in decent shape if he finishes second or third in Iowa and second in both New Hampshire and South Carolina. If his competition is just Cruz, he'll likely follow Romney's path to the nomination. If it's only Trump, Republican party actors in all the remaining states will mobilize everything they can for the Florida senator.

Of course, Rubio may fade, and one of the current also-rans could surge in the polls. Even if Rubio continues to slowly gain in the polls, the way things play out could still be different from how it looks now. For all we know, Huckabee could still win in Iowa, and Christie could take New Hampshire.

But if Rubio continues his gradual improvement in the polls and draws in more support from Republican party leaders, he won't be stopped just because none of the early states is a particularly good fit for him.

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Jonathan Bernstein, a politicial scientist and author, is a Bloomberg View columnist.