An early bit of conventional wisdom that's been forming about the 2020 Democratic presidential race is that "electability" will be a deciding factor for Democratic voters desperate to defeat President Trump. But the importance of this metric is highly overrated.

Or more precisely, we should be very clear that voters and pundits have much different ways of judging electability.

The view that above all Democratic voters mainly want somebody to beat Trump is backed up to some extent with polling data. A new CNN poll, for instance, found that 56 percent of Democratic voters said it was more important to them that the nominee be somebody "with a strong chance of beating Donald Trump" rather than a candidate who shared their positions on major issues.

The problem comes when pundits then try to use this information to speculate on which candidates it will benefit the most. That often leads to the assumption that the electibility concern will propel Biden over other more ideologically pure candidates.

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However, it's important to emphasize that the candidates who pundits may consider electable are not the same candidates who actual voters may decide are electable. And people are more inclined to assume candidates that they're rooting for can pull off a win in the general election. Part of the argument that ideologues often use, in fact, is that their party loses when it tries to be a more moderate version of the opposing party rather than making a strong, principled case and drawing a true contrast. Supporters of Sen. Elizabeth Warren, D-Mass., who believe socialist policies can pass through the U.S. Congress aren't likely to decide that they should vote for Biden because some poll showed him doing better against Trump. They will just convince themselves that Warren is the best candidate against Trump.

This phenomenon was quite visible in the 2016 Republican nomination battle. Poll after poll showed Trump was the weakest candidate against Clinton, and yet polls of Republicans consistently saw him as most electable. One poll in Oct. 2015 found seven in 10 Republican voters saw Trump as electable, more than any other candidate. The next highest number was current HUD Secretary Ben Carson. They happened to be the two leading candidates as voters gravitated toward political outsiders.

At the time, data showed Trump with high unfavorable ratings, and Sen. Marco Rubio, R-Fla., polled much better against Hillary Clinton. But voters didn't decide to choose between their values and electability, they just decided that the person that most closely represented their values was electable, no matter what the polls said.

The 2016 experience is even more likely to convince Democratic voters that they should discount arguments about who is electable. Not only did Republicans ignore that advice and nominate Trump, but establishment Democrats were convinced that Clinton, as a more conventional candidate, was much more electable than Sen. Bernie Sanders, I-Vt. Yet just like establishment Republicans, they turned out to be wrong.

So ultimately, I don't think Democrats are going to choose based on electability. They are going to decide who they like first, and then convince themselves that that candidate is electable.