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.