WASHINGTON — Is the race for 2020 already over on the Democratic side?

History shows that candidates who aren’t already polling in the top three rarely win the nomination, meaning that hopefuls other than former Vice President Joe Biden, Vermont Sen. Bernie Sanders and El Paso Rep. Beto O’Rourke need to step up their game, fast.

Polls aren’t perfect, and polls this far from the primaries aren’t overly reliable.

But being in the top three at this stage is a strong indicator of staying power.

In seven of the last nine presidential primaries without an incumbent, the eventual nominee was already in that tier by January of the year before the election.

That’s next month — a year before voters in Iowa and New Hampshire start to winnow the field.

Biden has generally topped surveys of Democrats.

O’Rourke, catapulted to national prominence in a failed bid to oust Texas Sen. Ted Cruz, says he hasn’t yet begun the process of deciding whether to run.

“He came out of nowhere,” said Tim Malloy, assistant director of the Quinnipiac University Poll. “If you’re Beto O’Rourke or his people, you have to look at this and say, a year ago most Americans didn’t know who he is and now he’s ranked third in national polling — that’s not discouraging.”

Some of the potential Democratic contenders for the 2020 presidential nomination. Top row: former Vice President Joe Biden, Sens. Cory Booker, Kamala Harris and Elizabeth Warren. Bottom: Sens. Sherrod Brown and Bernie Sanders, Rep. Beto O'Rourke, and Michael Bloomberg, former New York City mayor. (AFP / Getty Images)

Still a blank slate

A Quinnipiac survey released Wednesday that focused on favorability ratings showed O'Rourke well-positioned.

Biden’s 53-33 percent favorable/unfavorable rating is the best among potential Democratic contenders for 2020 — and well ahead of President Donald Trump's 40-56 ratio.

The party’s 2016 nominee, Hillary Clinton, is even further underwater at 32-61.

Sanders’ rating is about split, 44-42.

O’Rourke’s rating: 24 favorable, 20 percent unfavorable, with 55 percent of voters polled nationally saying they don’t know enough about him to have an opinion.

Democrats have an overwhelmingly positive view of O’Rourke, as they do of Biden and Sanders. Biden aides have been floating the idea of the 76-year-old former vice president picking the 46-year-old Texan as his running mate — a ploy that may be intended to smoke out — or box out — O'Rourke by reminding voters that he’s relatively inexperienced and untested on the national stage.

Sanders is 77.

A Draft Beto group this week announced a drive to raise $1 million, to be waiting for the Texan in an escrow account if he jumps into the race.

O’Rourke raised more than $80 million in the race against Cruz, setting a national record for a Senate nominee, though he had depleted his coffers by the end. But with proven fundraising prowess, he could be formidable. And he managed to hold Cruz below 51 percent in a state that hasn’t elected a Democrat statewide since 1994.

All of that attracted national attention and thrilled party activists.

“The fact that he’s young, incredibly articulate and looks like a Kennedy doesn’t hurt,” Malloy said of O’Rourke. “It says that he’s not going to go away.”

What the polls say

Since 1996, according to a CNN analysis, Donald Trump is the only nominee in either party who wasn’t even in the top five in polls taken between the midterm elections and the next January. He didn’t jump into the race until June 2015.

The history of anyone outside the top three having a rough time surviving the primaries stems from the average of early polls, and the evidence continues to mount that the three B's — Biden, Bernie and Beto — are the ones to beat.

A Harvard CAPS/Harris Poll two weeks ago found them in the top three, albeit with O'Rourke in single digits.

A CNN/SSRS survey taken Dec. 6-9 showed Biden at 30 percent and Sanders at 14 percent among Democrats nationwide, with O'Rourke third at 9 percent — more than double his support from two months earlier, leaping ahead of 2004 presidential nominee and former Secretary of State John Kerry and three senators, Kamala Harris, Cory Booker and Elizabeth Warren.

A CNN/Des Moines Register poll released Saturday showed the same trio at the top of the list for likely caucusgoers in Iowa. O'Rourke was at 11 percent. No one else broke double digits.

The Texan topped a straw poll of progressive activists released Dec. 11 by MoveOn.org.