Democratic presidential candidates Hillary Clinton and Sen. Bernie Sanders (Vt.), right, join Senate Minority Leader Harry M. Reid (D-Nev.) on stage before the Battle Born/Battleground First in the West Caucus Dinner on Jan. 6 in Las Vegas. (Alex Wong/Getty Images)

Close your eyes for a minute and imagine it’s Feb. 10. In the past nine days, Sen. Bernie Sanders (Vt.) has beaten his Democratic presidential challenger Hillary Clinton in the Iowa caucuses and the New Hampshire primary. There won’t be another vote for 10 more days (Nevada), and then it’ll be another week until South Carolina, the last of the big four early states, votes.

That scenario would be a total nightmare for Clinton. Period. It’s also a lot more likely to go from fantasy to reality than most people — including most establishment Democrats — understand.

Consider two polls conducted by the Wall Street Journal, NBC and Marist College in Iowa and New Hampshire that were released Sunday. In Iowa, Clinton has 48 percent, Sanders has 45 percent, and former Maryland governor Martin O’Malley has 5 percent. In New Hampshire, it’s Sanders in the lead with 50 percent, with 46 percent for Clinton and 1 percent for O’Malley.

Even if you accept that these surveys are a snapshot in time and take a step back to look at the broader polling picture, the idea of Sanders sweeping the first two states remains plausible.

Bernie Sanders enjoys strong support among young voters, but they'll need to turn out at the polls if he wants to win the Democratic nomination. (Peter Stevenson/The Washington Post)

In Iowa, Clinton’s lead on Sanders is 10 points, according to the RealClearPolitics average of polling conducted in the race. In New Hampshire, Sanders’s lead over Clinton is just shy of five points, according the RCP polling average.

There’s little question that Iowa is the tougher nut to crack of the two states for Sanders. Although Clinton finished third in the state’s 2008 caucuses, she and her team have worked extremely hard to ensure that she is well organized and well funded in the state to avoid a repeat of that performance.

Sanders’s strong liberal positions on, well, almost everything — including his early opposition to the war in Iraq — should endear him to the liberals who tend to make up a large chunk of the caucus electorate. In 2008, a majority of Iowa Democrats in the caucus exit poll identified themselves as either “very” (18 percent) or “somewhat” (34 percent) liberal.

In New Hampshire, Sanders has steadily run ahead of Clinton. Of the past 10 polls in the state, Clinton has led just three — and never by anything outside of the surveys’ margins of error.

Clinton allies have long insisted that Sanders’s geographic proximity to New Hampshire makes him naturally competitive in the state. And, they argue, a Sanders victory in the state would effectively be a “favorite son” situation — rendering it largely meaningless.

But back-to-back wins in Iowa and New Hampshire would make it impossible for the Clinton team to make that case credibly. Sanders wouldn’t be a one-state phenomenon; he would be 2-0 in head-to-head matchups against the heavy favorite to be the Democratic nominee.

Now, I know what you’re thinking. Even if Sanders wins Iowa and New Hampshire, Clinton is still in fine shape, because the rest of the calendar is made up of much more racially diverse states — Nevada on Feb. 20, South Carolina on Feb. 27, and so on and so forth — where Clinton runs far better than Sanders.

True! But remember that politics is a changeable business. And that most normal voters (still) aren’t paying much attention to the process. If Sanders won the first two states, is it that hard to believe that the race could fundamentally shift — and not in a good way for Clinton — in the 10 days between New Hampshire and ­Nevada?

To me, the idea that the race is totally upended is at least as likely as the notion that Sanders winning the first two states wouldn’t affect much of anything in the states that followed.

Clinton and her team are very aware of the peril inherent in their present situation. She has launched an aggressive attack on a 2005 Sanders vote in favor of giving immunity from liability lawsuits to gun manufacturers, a strategy clearly designed to take some of the shine off the senator from Vermont in the eyes of Iowa liberals.

“I think that the excuses and efforts by Senator Sanders to avoid responsibility for this vote, which the National Rifle Association hailed as the most important in 20 years, points at a clear difference,” Clinton said Sunday on CBS’s “Face the Nation.” “It’s a difference that Democratic voters in our primary can take into account.”

The political reality for Clinton goes like this: If she wins Iowa, she almost certainly could weather a New Hampshire loss and go on to win the nomination. But, if Clinton comes up short in Iowa, look out. We could be in for a longer — and more competitive — race than anyone expects.