Senator Jon Tester, a Democrat from Montana, questions Jerome Powell, chairman of the U.S. Federal Reserve nominee for U.S. President Donald Trump, bottom right, during a Senate Banking Committee confirmation hearing in Washington, D.C., U.S., on Tuesday, Nov. 28, 2017. Andrew Harrer | Bloomberg | Getty Images

President Donald Trump heads to Montana on Thursday to jab at Sen. Jon Tester in his own backyard. But the Democratic senator appears unfazed as control of the Senate and the fate of the president's policy goals hang in the balance. Republicans have made Tester's seat a high-priority target in this year's midterm elections as they try to keep or expand their 51 seat to 49 seat majority in the Senate. The party has good reason to go after him: Trump triumphed in Montana in 2016, carrying the state by more than 20 points. The president is traveling around the country this summer to raucous, incendiary campaign rallies, aiming to boost Republicans and damage Democrats running in competitive Senate races. After going to North Dakota last week to aid GOP Rep. Kevin Cramer in his bid to unseat Democratic Sen. Heidi Heitkamp, Trump hopes to help Montana State Auditor Matt Rosendale in his effort to beat Tester.

Trump has attacked Tester with more venom than he has used in criticizing other Senate Democrats. He even called on Tester to resign after the Democrat raised public concerns about allegations made against White House physician Ronny Jackson, who later withdrew from consideration to be secretary of Veterans Affairs. The Defense Department's inspector general is currently investigating allegations that Jackson, a Navy rear admiral, oversaw a hostile work environment, drank on the job or allowed the overprescription of drugs. Jackson has denied the allegations. Yet while he has faced an onslaught, Tester has made little effort to appease a president whose popularity has appeared to dip in Montana since the resounding 2016 win. The Democrat has shown less deference to Trump than most of his red-state Democratic counterparts, suggesting he is not sweating the re-election fight. Ahead of the president's stop in Great Falls, Montana, Tester tried to pre-empt Trump's attacks, which will likely cast the senator as a liberal obstructionist who hamstrings the president's immigration and economic agendas. “We’re glad President Trump is finally coming to Montana, after Jon has invited the Administration several times to Montana to discuss topics important to Montanans," said Chris Meagher, a spokesman for Tester's campaign. “Unfortunately, it looks like this will turn out to be a partisan attack, rather than a real opportunity to discuss real issues facing Montanans – like better infrastructure, schools, holding the VA accountable, or the Farm Bill." The senator took out tongue-in-cheek newspaper ads Thursday throughout the state thanking Trump for signing 16 bills that he sponsored or co-sponsored. "Welcome to Montana, and thank you President Trump for supporting Jon's legislation to help veterans and first responders, hold the VA accountable, and get rid of waste, fraud and abuse in the federal government," the ad reads. As the newspaper ad reflects, the Montana senator has certainly not been one of the liberal stalwarts in opposition to Trump, and has seemed careful about when to publicly criticize the president. He has voted with Trump's priorities more often than most of his Democratic colleagues. But Tester's behavior reflects a view that he does not fear the competitive challenge from Rosendale in one of the pivotal races to determine Senate control for the next two years. The stakes are huge: the Senate makeup could determine whether Trump confirms another young, conservative justice to the Supreme Court, or whether the GOP can pursue the president's immigration and health-care policies next year.

A popular Democrat in a GOP state