Democrats have run TV ads accusing North Carolina Sen. Richard M. Burr of profiting from his office, undermining Medicare, and exacerbating congressional gridlock.  

And yet, a month before Election Day, the party’s candidates and their allies have conspicuously and surprisingly avoided one subject altogether in their on-air barrage: Donald Trump.

Neither the Democratic Senatorial Campaign Committee nor North Carolina’s Democratic Senate nominee Deborah Ross has run a Trump-themed ad against Burr. Instead, they’ve hammered the Republican incumbent with the kind of well-worn attacks that Democratic campaigns have featured heavily in recent elections.

Trump’s absence in North Carolina might seem strange, but in many of the dozen top Senate races this election, leading Democratic groups and candidates have avoided using the GOP presidential nominee in their paid media campaigns.

The strategy is a far cry from how the candidates and their campaigns discuss Trump during press releases, interviews and speeches, where they mention the GOP leader so relentlessly it can often be hard to detect another message. It’s also far different from the strategy of many House Democrats and the Democratic Congressional Campaign Committee, which, of late, has leaned heavily on Trump in TV ads.

But top Democratic strategists say that in radio and TV ads — what strategists usually consider the most important messages of a campaign — they have consciously made a pitch to voters that doesn’t rely on the GOP standard-bearer. The hope, they say, is to exploit what they consider vulnerable issues for Republican candidates — while also trying to insulate themselves from the ups and down of an unpredictable presidential election.

“I think Hillary will do very, very well, and that will benefit our candidates,” said Tom Lopach, the DSCC’s executive director. “But I also think our candidates are running on the issues important to their states and their constituents.”

The candidate’s campaigns, the DSCC, and the Senate Majority PAC (a super PAC linked to the Senate Democratic leadership) together constitute the overwhelming bulk of ad spending for Senate Democrats.

And each entity has avoided running a Trump-related TV or radio ad in Pennsylvania, Illinois, Wisconsin, Missouri, Indiana, or North Carolina. (Russ Feingold’s campaign in Wisconsin ran one digital Trump ad, according to a campaign spokesman.) All six states feature a competitive Senate race.

The DSCC independent expenditure arm has not used Trump in any of its ads.

Democrats aren’t avoiding Trump everywhere: Last month in Nevada, Democratic nominee Catherine Cortez Masto and the Senate Majority PAC began focusing heavily on linking Republican Senate nominee Joe Heck to his party’s top-of-the-ticket presence.

Party strategists caution that more Trump-related ads could soon arrive in the remaining five weeks before Election Day, even in places where the message hasn’t been deployed so far. Trump’s sliding popularity, evident in polls taken since the first presidential debate, could convince Democrats that the GOP leader is too toxic to ignore on air.

Republicans roll their eyes at the suggestion that Democrats have done anything significant beyond discussing Trump. They point to events like the one Monday, when after a debate, the campaign for New Hampshire Democratic Senate nominee Maggie Hassan focused entirely on GOP Sen. Kelly Ayotte’s statement that Trump was “absolutely” a role model for children.

The DSCC, though not its independent expenditure arm, released a web ad on Tuesday highlighting the incident. 

“Democrats faced with weak Senate candidates and an incredibly unpopular presidential candidate have put all their eggs into one basket, and it’s starting to backfire,” said Andrea Bozek, a spokeswoman for the National Republican Senatorial Committee. “While on the other hand, Republicans have been laser-focused on running localized races and are in great shape heading into the last month of the election.”

Democrats say the near-absence of Trump in ads through the summer and early fall is rooted in several factors.   

In red states such as Missouri and Indiana, for instance, the respective Democratic nominees Jason Kander and Evan Bayh have assiduously avoided discussing Trump in any way, cognizant that he will likely win each state comfortably.

Democrats also say that the media are so saturated with news about Trump that they fear running ads about him wouldn’t tell voters anything new, especially in well-to-do suburbs where news consumption is high.

“While the earned media has been dominated by Donald Trump, the paid media has been very specific to how Republican Senate candidate are out of step with their states,” said Martha McKenna, a DSCC veteran.

House Democrats have taken a different approach. On Tuesday, the independent expenditure arm of the DCCC released an ad linking Trump to Republican Rep. Jeff Denham in California’s 10th Congressional District, part of a fleet of recent Trump-focused ads from the group.

The divergent tacks, explained one party operative, lies in the different types of electorates present in select House districts and statewide races. Outside of cities, Trump struggles most in suburban-heavy, well-educated districts.

“In the House races, our opportunities are in the suburbs,” said one Democratic strategist, who requested anonymity to speak candidly. “We can cherry-pick the favorable demographics, whereas a Senate candidate cannot.”