If Sen. Bernie Sanders of Vermont wins the Democratic nomination, then everything we know about presidential primaries can be thrown out the window. I say this despite new polls this week from Morning Consult and Suffolk University giving Sanders more than 30 percent of the vote and closing within 12 percentage points of Hillary Clinton in New Hampshire. These polls have already generated tons of headlines, but it’s important to keep in mind that even presidential steamrollers hit speed bumps and even — gasp! — lose states.

Consider the top five candidates in early polling in modern primary history: Republican Ronald Reagan for the 1980 nomination, Republican George H.W. Bush for 1988, Republican George W. Bush for 2000, Republican Bob Dole for 1996 and Democrat Al Gore for 2000. All went on to win at least 59 percent of the national primary vote and easily take the nomination. All were polling at 35 percent or better in Iowa, New Hampshire and national primary polls at this point in their campaigns.

And yet, all but Gore lost the Iowa caucus or the New Hampshire primary. In fact, all but Gore lost at least six caucuses or primaries.

Gore had an easier time than anyone else — he won more than 75 percent of the national primary vote and all 50 states — but even his campaign had its wobbly moments. Some polls had Bill Bradley wiping out Gore’s New Hampshire lead completely in the fall of 1999. Gore’s chief of staff, Ron Klain, was even forced out of Gore’s orbit in early August 1999.

Clinton looks as strong as — or stronger than — any of these past front-runners. She is near 60 percent in Iowa and nationally, and above 40 percent in New Hampshire. It shouldn’t be too surprising that Sanders is doing well in New Hampshire, Vermont’s neighbor. Sanders might win New Hampshire! He (or another Democrat) might win several states. Again, front-runners — even historically dominant front-runners — typically taste the bitterness of defeat at least a couple of times.

But the foundational flaws in Sanders’ candidacy are pretty easy to spot. Sanders may be polling well in mostly white New Hampshire, but he hasn’t been able to figure out how to earn more than 5 percent of the nonwhite vote, according to national polls. Nonwhite voters make up more than a third of Democratic primary voters nationally.

Indeed, it’s difficult to imagine why someone who has described himself as a socialist, has never competed for minority voters and has no roots within the Democratic Party should worry Clinton much. She might actually be relieved to be challenged by someone who has so little chance at winning the nomination. Let’s imagine a case where Sanders wins Iowa and New Hampshire. In that world, you’d likely see the Democratic establishment rush in to try to squash Sanders, much as Republicans did to Newt Gingrich in 2012 after he won South Carolina.

Regardless of what you think of Martin O’Malley (and you know how I feel), he at least has won minority voters, has roots in the Democratic party and wouldn’t be labeled as toxic in the general election. O’Malley is a pretty standard Democratic pol, and if he somehow looked capable of toppling Clinton, you can at least imagine Democratic bigwigs making peace with an O’Malley general election campaign.

Sanders has very little establishment backing: Of the 111 governors, senators and members of the House to have endorsed a Democratic candidate, 100 percent have endorsed Clinton. Only Gore in 2000 came close to winning this large a percentage of the endorsements at this point in the campaign. Clinton’s support comes from north, south, east, west, black, Latino and white.

Not only are early endorsements well correlated with the eventual outcome of the primary; in many cases, early state endorsers played a key role in helping faltering campaigns by providing strategic advice and organizational strength. Two examples:

In 1988, George H.W. Bush relied on the steady hand of New Hampshire Gov. John Sununu to beat challenger Bob Dole by almost 10 percentage points in the Granite State. Bush followed that up with a win in South Carolina, thanks, in part, to Gov. Carroll Campbell’s backing.

In 1996, Dole won Iowa, lost New Hampshire to Pat Buchanan and needed to win in South Carolina. Dole prevailed in the Palmetto State by more than 15 percentage points with the help of pretty much every Republican elected official in South Carolina and a slew of local religious leaders.

If Sanders makes a real run, Clinton is likely to respond the way past nominees have. She’s going to recast her message when necessary and rely upon the overwhelming support of those within the party. We’re already seeing it with regard to her positioning on trade and surrogate attacks on Sanders for his views on immigration.

But don’t be surprised if Clinton loses in a few contests. (Do be surprised if Clinton loses the nomination.)