Sen. Jon Tester was in trouble in a fresh Republican poll, as GOP challenger Matt Rosendale pulled even with the Montana Democrat at 44 percent.

The survey of likely voters from the National Republican Senatorial Committee, in the field Monday to Wednesday, had a relatively high margin of error — 4.47 percent. But in a polling memorandum shared with the Washington Examiner, the trend in NRSC polling revealed a targeted midterm election contest is gradually tightening as Republican advertising attacking Tester takes a toll on the incumbent's image.

"These shifting attitudes towards Senator Tester are impacting his standing on the ballot," pollster Brenda Gianiny, of Axis Research, wrote in a memo for the NRSC.

President Trump won Montana in 2016 and maintains a wealth of support in the state. But some senior Republicans, underwhelmed by Rosendale, Montana's elected state auditor, have downgraded the party's chances of ousting Tester. Judging by the NRSC's continued spending in the race — $3 million so far — the committee believes the senator is beatable.

In publicizing this latest internal poll, the NRSC undoubtedly wants to signal to other Republican groups, plus donors and activists, that Montana is worth their investment. The data was gleaned from live interviews with registered voters considered likely to show up on Nov. 6 and who were reached over landlines and cellphones — all hallmarks of a quality survey.

The ballot test showed Tester and Rosendale tied at 44 percent, with 4 percent choosing Libertarian Rick Breckenridge and 8 percent claiming to be undecided. Within those numbers, Tester and Rosendale were even among supporters who said they were "definitely" planning to vote for them. Trump's job approval in the state is solid, ranging from 53 percent to 58 percent in the four recent polls Axis has produced for the NRSC — two in July, one in August, and this latest one.

Per the polling memo, additional findings include:

