(CNN) First things first: The theme song of the week is from the show Off The Rack starring Ed Asner.

This is identical to a January Monmouth University poll when Biden scored the same 80% favorable rating and 9% unfavorable rating with Democrats.

Biden has been the polling frontrunner throughout the early stages of the 2020 Democratic primary. Yet, as I've noted before , there are many reasons to believe his advantage won't hold.

Not surprisingly, a statistical analysis of his congressional voting record suggests Biden is among the most moderate in the 2020 field.

The problem for Biden is obvious: the Democratic electorate is moving to the left. Whether you examine Gallup or the Pew Research Center's trendline , Democrats have become a lot more liberal over the last 25 years. Gallup, for instance, showed that the percentage of Democrats who call themselves liberal has more than doubled from 25% in 1994 to 51% today.

But I would argue that looking at ideology through the normal left-right spectrum doesn't get at Biden's appeal. Voters like Biden not because they don't know or don't understand his left-right ideology (though he does better with moderate Democrats than liberals).

Democrats like Biden because he was the vice president to the most popular Democrat in the country, Barack Obama. Biden's best chance of winning is not to run from his record. It's merely to focus on his most recent record. Biden should point voters to his time as Obama's number two. It's far from a guarantee that it will work, though it really could help ameliorate the potential flaws of his past record in the Senate.

Obama is still a rock star to Democrats throughout the nation. His favorable rating stood at an astounding 97% among Democrats in a CNN poll taken last year

To give you an understanding of how popular Obama is with Democrats, compare his popularity among them to President Donald Trump's popularity with Republicans. Trump continuously aims to please his base at the detriment of the center of the electorate. It has worked: His approval rating was 90% among Republicans in the latest Gallup poll . Even so, Obama is 7 points more popular with Democrats than Trump is among Republicans.

As Michigan State University Professor Matt Grossmann has pointed out , Democrats are more likely to identify as an "Obama Democrat" than they are with any ideological identification. That is, more Democrats call themselves an "Obama Democrat" than call themselves a "liberal Democrat," "progressive" or "Democratic Socialist".

Back in 2016, there was a very good test about whether Democrats wanted to continue the ways of Obama or go further to the left. In all 27 states with an entrance or exit poll in the primary, Democratic primary voters were asked whether the next president "should continue Obama's policies," "be more liberal" or "be more conservative."

More voters in 24 of the 27 states said the Democratic nominee should continue Obama's policies than be more liberal. In one of those states (West Virginia), the plurality position was actually that the next president should be more conservative. In the other two, support for a more liberal president didn't even top 50%. In other words, there wasn't a single state where a majority of Democratic primary voters said the next president be more liberal than Obama.

Now obviously, it's not 2016 anymore. That said, there's good reason to believe what the exit polls revealed about the Democratic electorate still holds given how popular Obama is with Democrats.

I should also point out that these poll findings don't mean that the 2020 Democratic nominee is going to be moderate or only somewhat liberal. In fact, it's probably the safest bet at this point to think the 2020 nominee will be further to the left than Obama given the growing number of liberals within the party.

What these polls do indicate is that the 2020 Democratic nominee is likely to be someone who can best say they are continuing the legacy of the Obama administration and building on its success.

The former vice president for Obama has a good claim to the Obama mantle, and it's a big reason why Biden is a formidable 2020 candidate.