If anyone asks, Gov. Tim Walz of Minnesota has an endorsement in the Republican presidential contest — his Red River neighbor, Gov. Doug Burgum of North Dakota.

“I’m not a Republican, I’m not going to vote in the Republican primary, but if I did I’d vote for him,” Mr. Walz said as Mr. Burgum addressed a small and not terribly rapt audience at the Iowa State Fair’s political soapbox.

The Walz endorsement — he’s a Democrat — probably won’t do much for Mr. Burgum in Iowa’s Republican caucuses. Mr. Walz came to the fair to tout his party’s policies and promote President Biden’s re-election campaign amid the thicket of Republican White House hopefuls who aim to knock Mr. Biden out of the Oval Office.

During a tour of the fair’s midway, Mr. Walz ticked through all the usual Biden campaign talking points, discussed how Minnesota’s state fair is superior to Iowa’s (“There’s no shame in being second,” he said), wondered if anyone would heckle former Vice President Mike Pence during his appearance Thursday afternoon and chowed down on a pork chop on a stick.

With an entourage that included Rita Hart, the Iowa Democratic Party chair, and Sarah Trone Garriott, a state senator from West Des Moines, Mr. Walz said he viewed the political happenings here with the curiosity of a first timer, wondering why Mr. Burgum hadn’t done more to organize supporters to hear him speak and confessing that he doesn’t believe any of the dozen Republican rivals to former President Donald J. Trump will emerge as the G.O.P. nominee.

“There’s no doubt in my mind whatsoever” that Mr. Trump will be the Republican presidential nominee, Mr. Walz said.

So what did he think the rest of the Republicans were doing making successive pilgrimages to the state fair to sweat through a weekend of fried food?

“It’s hard to tell,” he said. “That’s what I’m here to watch and see.”