A new national poll is the latest to show Joe Biden with the edge over President Trump in the all-but-certain November general election showdown.

But in a potentially troubling sign for the former vice president and de facto Democratic nominee, the survey also indicates that Trump supporters are much more committed to voting for their candidate than Biden backers.

THE LATEST FOX NEWS POLLING IN THE 2020 PRESIDENTIAL CAMPAIGN

The former vice president has a 47-43 percent advantage over Trump in a Grinnell College poll released Wednesday and conducted March 27-30.

That’s consistent with other recent live telephone operator national polling released in recent days. Biden edged Trump 49-47 percent in an ABC News/Washington Post survey conducted March 22-24 and topped the president 49-40 percent in a Fox News poll in the field March 21-24.

But looking past the topline numbers, the Grinnell survey indicates that 82 percent of likely voters who said they’ll support Trump say their minds are made up. That number drops to 55 percent for Biden supporters.

Biden has not yet secured the nomination and his chief rival, Vermont Sen. Bernie Sanders, remains in the race, though acknowledges his path is narrow.

The numbers in the Grinnell survey – which was conducted by the well-known polling outfit Seltzer and Co. – follow figures in the ABC News/Washington Post poll which pointed to an enthusiasm problem for Biden.

THE LATEST FROM FOX NEWS ON THE 2020 PRESIDENTIAL CAMPAIGN

According to the ABC News/Washington Post poll, 53 percent of Trump supporters said they’re “very enthusiastic” about supporting the president, but only 24 percent of those backing Biden said the same about supporting the former vice president.

The Grinnell College national poll was conducted by live telephone operators – with 777 likely voters questioned. The survey’s sampling error is plus or minus 3.5 percentage points.