Biden topped Trump by 16 percentage points—54 to 38%—in the survey, conducted Aug. 21-26. That’s up slightly from 53-40% in June.

Vermont Senator Bernie Sanders, Massachusetts Senator Elizabeth Warren, California Senator Kamala Harris and South Bend Mayor Pete Buttigieg also led Trump in hypothetical match ups.

On the economy, 37% of voters said conditions were worsening, with just 31% saying the situation is getting better — a troubling sign for Trump, who has made taking credit for a strong economy a centerpiece of his campaign messaging.

The poll appears unlikely to help any other Democratic candidates qualify for the next round of candidates debates in Houston in September. Wednesday is the deadline to meet the debate criteria of having 130,000 donors and polling at least 2% in four qualifying polls.

About half of the current field is yet to qualify, even accounting for the three recent dropouts: John Hickenlooper, Jay Inslee and Seth Moulton. If one more candidate hits the threshold, the event will be held over two nights, with slots randomly assigned. Billionaire investor Tom Steyer looks to have the best chance to get in but failed to top 1% in this latest poll.

For the poll, conducted from Aug. 21-26, Quinnipiac University surveyed 1,422 self-identified registered voters nationwide with a margin of error of 3.1 percentage points. The survey of 648 Democratic voters and independent voters who lean Democratic has a margin of error of 4.6 percentage points.

More must-read stories from Fortune:

—Will gaffes hurt Biden’s chances of a 2020 win? Strategists are divided
—These are the 2020 senate races to watch
—What is BDS? Boycott, Divestment, and Sanctions explained
—When does Congress reconvene? August recess, explained
—Trump thinks he is winning the trade war, but the data tell a different story
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