I say this only half-jokingly: I wonder if Fox will find an excuse to discontinue, or at least scale back, its polling of the election as the campaign wears on. Trump has already warned them publicly that he’s willing to promote their competition if anchors like Shep Smith keep knocking him. Bad polling bothers him more since it suggests that the people themselves dislike him, not just Fox’s 3 p.m. guy. If he starts slapping the “fake news” label on Fox because of its polls, who knows what effect that’ll have on Fox’s viewers.

I bet the network will come up with a reason to poll less frequently. Or nudge the anchors to at least not mention the numbers on the air.

This data comes from the same survey I wrote up yesterday. The key number isn’t the share won by the Democrat in each match-up, it’s the share won by Trump. What Fox is telling us here is that, at this moment in time, fewer than 40 percent of the country is committed to reelecting him no matter what other name you throw at them.

One stat from Fox’s write-up of the poll jumps off the page: “Voters who have a negative view of both Biden and Trump back Biden by a 43-10 percent margin in the head-to-head matchup…” Trump famously cleaned up in key states in 2016 among voters who disliked both him and Hillary. He was the lesser of two evils to undecideds then. Against Biden, he’d face an opponent who’s not only more personally popular than he is but who appeals more than Trump does to people who are disinclined to support either.

Another reason for Biden’s stronger showing against Trump is older voters. Among voters aged 45 or older, Sanders, Warren, and Harris each lead Trump by a mere one or two points. Biden leads him by eight. That’s another demographic that was key to Trump’s victory in 2016 and which is wavering now:

In 2016, despite polling showing an advantage for Democrat Hillary Clinton, voters over 65 backed Mr. Trump in the presidential election by a 52%-45% margin, according to exit polls. With still more than a year before next year’s election, 41% of seniors in a Wall Street Journal/NBC News poll in June said they would prefer to see Mr. Trump re-elected, while 48% favored a generic Democrat to win in 2020. That comes as 46% of seniors said they approve of Mr. Trump’s performance in office, slightly higher than his 44% overall approval rating…

In a July Wall Street Journal/NBC News poll, Mr. Trump trailed former Vice President Joe Biden among seniors in a theoretical head-to-head contest, 55% to 43%. Voters over 65 also favored Vermont Sen. Bernie Sanders and Massachusetts Sen. Elizabeth Warren over Mr. Trump by 7 and 8 percentage points, respectively.

Younger adults dislike Trump so he needs to pile up his margin among seniors to offset that deficit. One of the strongest arguments for nominating Grandpa Joe, in other words, ironically may be that his age and decades of familiarity to seniors could undercut Trump among his own age cohort in the electorate. In fact, when Fox asked Democratic primary voters if they prefer a nominee who will “get American politics back to normalcy” as president or a nominee who will “fundamentally change the way things work in Washington,” the group that broke hardest for “return to normalcy” was — you guessed it — voters aged 45 or older, at 66/30. Older Americans, at least those who lean left, want to go back to what they consider the good old days. Naturally that benefits the old centrist former VP in the primary, and might benefit him again in the general election.

Fox polled Democrats on their primary preferences too, of course. That is … some shift since March:

Biden and Harris haven’t budged an inch. All the momentum is from Sanders to Warren. Warren was also second in a poll this week of South Carolina, albeit only slightly ahead of Bernie there. When I suggested a few weeks ago that Warren was the biggest threat to steal votes from Bernie, a bunch of smart politicos tut-tutted me that it’s actually Biden who’s the biggest threat since he and Bernie both appeal to white working-class Dems. If you believe Fox, though, I was right: Virtually all of the migration out of Sanders’s camp has ended up in Warren’s. It may be that the rump of Bernie’s current support consists of those blue-collar white voters who are also considering Biden, such that we might see an uptick for Grandpa Joe if Sanders begins to fade from the race. But for now it looks like simple cause-and-effect between Warren’s rise in the polls and Bernie’s decline. Progressives, the sort of people who are further left than mainstream liberals but not so far left that they identify as DSA, seem to prefer her to him. She’s winning the battle for the left “lane,” if such a thing exists.

Oh, last thing: The most popular politician in the Democratic Party by far is Barack Obama, who pulls a 93/6 favorable rating in Fox’s poll. It may be annoying to hear Biden mention his association with O every three seconds on the stump, but it’s not stupid of him to do so.