Bevin is likely to make Trump a central part of his closing argument, and Trump has made last-minute trips to heavily Republican areas a staple of his campaign arsenal for GOP allies. Bevin has portrayed himself as a staunch White House ally and has aired TV ads which prominently feature the president. Trump won Kentucky by nearly 30 percentage points in 2016.

The offensive comes amid Republican concerns over Bevin’s standing. Bevin has consistently ranked as one of the least popular governors in the country, and he faces a formidable Democratic opponent in state Attorney General Andy Beshear, the son of a popular former governor.

Bevin recently orchestrated a shakeup of his senior campaign staff. Republican operative Michael Antonopoulos, who has been advising the governor throughout the race, has taken over operational control from campaign manager Davis Paine. The move, according to two people familiar with the matter, was at least partly related to the handling of a poorly attended summer rally that Donald Trump Jr. held for Bevin.

But Republican officials are increasingly expressing optimism about the Kentucky contest. Recently-completed voter modeling conducted by the Republican National Committee showed Bevin leading by 3 percentage points. The results, according to one person familiar with the data, represented a marked improvement for Bevin compared to the committee’s previous findings in the race.

Democrats, however, insist they have the upper hand. The Democratic Governors Association's modeling shows Beshear up 4 percentage points, according to a person familiar with the matter.

Kentucky is one of three conservative states holding gubernatorial races this fall, and a loss in any of the three contests would likely set off Republican alarm bells. Trump is scheduled to hold a Friday evening rally in Louisiana, where the party is trying to ensure that Democratic Gov. John Bel Edwards is forced into a November runoff.

Senate Majority Leader Mitch McConnell and other members of the Kentucky congressional delegation are scheduled to headline a fundraiser for Bevin next week in Washington, according to an invitation obtained by POLITICO. McConnell, who is up for reelection next year, fended off Bevin in a bitter 2014 Senate primary but has put aside the past rivalry and instructed his team to help the governor.