President Donald Trump’s attacks on Montana Sen. Jon Tester have energized the GOP in the state ahead of the midterms, but it’s unclear if voters will be swayed to dump the populist incumbent, The Washington Post reported Sunday.

Tester — who enraged the president by derailing the nomination of Ronny Jackson to head the Department of veterans Affairs— has an image that could be tricky to brand, according to the Post.

“Our guy can take out a transmission on a John Deere tractor, okay?” Butte voter and Tester supporter Geoff Gallus told the Post. “That’s meaningful.”

Another Butte Democrat, Marine Corps veteran Tom Barsanti, a Democrat, told the Post that Trump’s attacks on Tester could backfire.

“Keep the federal government out of your state,” he said of the state’s attitude toward Washington. “And the federal government, who’s the president, has just interjected into your state.”

Tester, who still works on his family farm, appears to be letting the Trump attacks — including his call for Tester’s resignation — roll off his back.

“I’m going to do what I’m supposed to do, and the president is going to do what he’s going to do,” he told The Montana Standard.

“I’m not worried about it.”

A top Republican donor on the sidelines of the race told the Post, however, the Trump-Tester feud has made him consider investing money there.

“This race was not on my radar, but I am now paying attention and will probably contribute to the Republican nominee,” Dan Eberhart, a wealthy oil industry executive and GOP fundraiser with business ties in the state, told the Post.

White House Legislative Affairs Director Marc Short said he expects Trump will travel to Montana “before the fall,” the Post reported.

“If this was October 16, yeah I’d be a happy camper,” Joe Dooling, chairman of the Republican Party in Lewis and Clark County, home to the state capital of Helena. “By the time October comes around, there’ll be a new issue.”