(CNN) Democratic Sen. Claire McCaskill's campaign is trying to persuade Missouri voters that she is not "one of those crazy Democrats," with a radio ad airing during the final stretch of her heated re-election fight.
The ad, which has been on air in mid-Missouri for roughly the past week, is part of McCaskill's closing argument in one of the country's most closely watched Senate races. As a Democrat in a state that backed President Donald Trump by double digits in 2016, McCaskill has touted her moderate credentials and urged voters to look at her accomplishments, not her party ID.
McCaskill's campaign appears to be doubling down on that message in the campaign's final days. In a new television ad released Tuesday by McCaskill's campaign, featuring veterans who support McCaskill, one man says of the incumbent senator, "you don't have to like her," before pushing back on Republican lines of attack and praising her work in the Senate.
The radio ad takes that message a step further, however, attempting to differentiate McCaskill from unnamed "crazy Democrats."
The ad features two middle-aged men discussing the Senate race between McCaskill and state Attorney General Josh Hawley, a Republican, whom the narrators describe as "a man in a hurry."
"And hasn't Hawley been caught hanging at the gym and out buying wine during work hours?" one man asks, referring to photos that surfaced of Hawley earlier in the campaign.
The men then turn to McCaskill, with one conceding, "I don't always agree with Claire McCaskill."
"But she works hard, fighting against those tariffs, doing all those town halls," the man adds. "Claire's not afraid to stand up against her own party."
"Yep," the second man chimes in, "and Claire's not one of those crazy Democrats. She works right in the middle and finds compromise."
The ad appears designed to win over skeptical Trump voters, whose support McCaskill will need to best Hawley. But the phrase "crazy Democrats" could alienate some voters in McCaskill's own party at a moment when she is counting on their enthusiasm.
State Sen. Maria Chappelle-Nadal, a Democrat whose district includes Ferguson, told CNN she believes the ad could refer to African-American voters in the state's cities, among other subsets of the Democratic base.
McCaskill "is calling her base in the urban areas crazy Democrats," Chappelle-Nadal said, "and she's relying on those so-called crazy Democrats to make sure she wins."
McCaskill last year called on Chappelle-Nadal to resign after she expressed hope that Trump would be assassinated. Chappelle-Nadal later removed the post and apologized but refused to step down.
Chappelle-Nadal decided previously that she plans to write in a candidate rather than vote for McCaskill, who Chappelle-Nadal says has been "very disappointing."
A spokesperson for McCaskill's campaign did not respond to a request for comment regarding the ad.
CNN polling from earlier this month found the Missouri Senate race in a virtual dead heat.
This story has been updated with additional context about McCaskill and Chappelle-Nadal.