HELENA, Mont. — U.S. Sen. Jon Tester gave President Trump a tongue-in-cheek welcome to Montana Thursday by taking out a full-page ad in more than a dozen newspapers thanking him for signing 16 bills the Democrat sponsored or co-sponsored.

Mr. Trump was scheduled to hold a rally in Great Falls on Thursday to campaign for Tester's Republican challenger, State Auditor Matt Rosendale. The president has made the Montana Senate race a priority after he blamed Tester for derailing the nomination of his first Veterans Affairs nominee, White House physician Ronny Jackson.

Tester's ad, which ran in the Great Falls Tribune and in newspapers across rural northern and eastern Montana, sought to undermine the president's efforts to boost Rosendale by pointing out that he and the president agree on several issues.

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"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 read.

The Tester campaign also planned a statewide radio ad campaign to run through the weekend touting his bills that Mr. Trump has signed.

Tester is one of 10 Senate Democrats running for re-election in states that Mr. Trump won in the 2016 election. Mr. Trump singled out Tester in April, saying the farmer from Big Sandy "will have a big price to pay" for releasing allegations against VA nominee Jackson that included drunkenness, overprescribing medication and fostering a hostile work environment. Jackson denied the claims, but withdrew his nomination.

Montana is the latest stop on Mr. Trump's midterm campaign tour, designed to boost Republicans as well as advocate for his first 18 months in office. He recently made a similar trip to North Dakota and is expected to keep traveling throughout the summer.

In Great Falls, Mr. Trump plans to promote his record on the economy and national security, said a person familiar with the president's plans, adding that Mr. Trump would stress his recent moves on immigration and foreign policy as well as the low unemployment rate. The person was not authorized to discuss the plans publicly and spoke to The Associated Press on condition of anonymity.

The president is also expected to paint Tester as an "obstructionist" and embrace Rosendale as a better fit for the state that he won by 20 points.

The visit comes less than two weeks after his eldest son, Donald Trump Jr., campaigned for Rosendale in Billings.

Rosendale, who is seeking to deny Tester a third term and give Montana an all-Republican congressional delegation, said Mr. Trump has focused on the race because of Tester's "liberal obstruction."

Montana, a purple state that elects both Republicans and Democrats to statewide offices, strongly supported Mr. Trump in the 2016 election, leading both candidates to compete for Trump supporters. Rosendale said he'll back Mr. Trump's agenda, while Tester said he'll support the president when it's in the state's interests and oppose him when it's not.

Tester planned to spend Thursday listening to farmers' and business owners' concerns about Mr. Trump's import tariffs and was expected to be driving back to his farm when the president spoke, spokeswoman Marnee Banks said.