A trio of Democratic senators running in some of the most competitive races in the country are opting against attending the Democratic National Convention this week in Chicago, even as their party looks to display a heightened level of enthusiasm and unity for newly minted presidential nominee Kamala Harris.

Sens. Sherrod Brown of Ohio, Jon Tester of Montana, and Jacky Rosen of Nevada are all not planning to attend the four-day gathering, their offices said. Other Democrats in battleground state races, including Sen. Bob Casey of Pennsylvania, Rep. Elissa Slotkin of Michigan and Sen. Tammy Baldwin of neighboring Wisconsin, are planning to attend at least some of the gathering.

Brown and Tester represent states that Donald Trump carried by comfortable margins in 2016 and 2020, while Rosen represents Nevada, one of the most heated battleground states in the country for any Democrat. The absence of Brown, Tester and Rosen comes as Democrats attempt to preserve their narrow Senate majority with the possibility that a Republican pickup in any of these races could swing control of the chamber in November. Of the three senators skipping the Democratic confab, Rosen has looked the most favorable for Democrats, but even some in the party privately maintain that public polling hasn’t fully captured how close the race is.

The explanations for why each candidate isn’t attending the DNC vary. Brown’s campaign said the senator and his team have “been planning to be in Ohio for months,” listing a series of cities he will be visiting instead. But Brown has not avoided backing the Democratic presidential ticket; he endorsed Vice President Kamala Harris for president after President Joe Biden exited the race in late July.

In Montana, Tester is planning to go to a fundraiser in Missoula and a Pearl Jam concert at the University of Montana this coming week. The senator, who has not yet endorsed Harris for president, planned to spend August meeting with Montanans and farming.

As for Nevada, a Rosen campaign spokesperson stressed Thursday that the senator does support the Harris-Walz ticket “and was glad to join them on the campaign trail in Las Vegas this past weekend” but she is also “focused on her own reelection and will be talking with Nevada voters during the week of the convention.” Rosen was with Harris and Minnesota Gov. Tim Walz, Harris’ running mate, during a rally in Las Vegas earlier this month. Rosen did not attend the DNC in 2016, when she was running for a House seat, or in 2020, a downsized, largely virtual convention that took place a couple years into her Senate term.

There’s no hard and fast rule for whether a candidate should attend their party’s convention, and every statewide race is different. Democratic strategists point out that a candidate’s time, especially in a close race, is their most valuable asset, and attending the DNC means spending some of that time with enthusiastic national Democrats rather than persuadable voters.

“For some of these candidates in really, really tough competitive races, what’s the advantage of going to Chicago for a few days? You’re not going to get a lot of coverage. All of these candidates are doing well raising money. It’s not as if they need to get out there to meet with Steven Spielberg or someone to raise money,” said Mark Longabaugh, a veteran Democratic strategist. “There’s not a lot of advantage to being in Chicago. Any of those senators, if they were not in a heated campaign, would absolutely probably be at a convention.”

Dave Chase, a veteran Democratic campaign manager who ran former Rep. Tim Ryan’s Senate bid in Ohio in 2022, argued that for these candidates, skipping the convention isn’t about bucking Harris in particular.

“I don’t think it’s necessarily a conversation about ‘are they with the vice president or not.’ I think no matter who the nominee is, you see folks in tough races generally skip these things to focus on their campaigns,” Chase said.

Brown and Tester, in particular, have cultivated specific brands that both Democrats and Republicans maintain has helped buoy them in tough races in the past. This cycle, Tester has made a point of showing that he is willing to buck his party and to take a more conservative approach. Brown has been able maintain a level of support in Ohio with an image as a populist Democrat who can still rally the support of an increasingly conservative voting population. In both cases, the two red state senators have made a point over past campaigns of demonstrating an independent streak from the lean of their state.

A former Senate Democratic chief of staff and campaign manager suggested that Democratic lawmakers and candidates who are going are mostly ones with speaking slots “that they feel will help with their base voters and give additional exposure for national fundraising.”

“I assume those who are staying home think speaking at the DNC does not help in their races and would rather spend those days campaigning in state,” the former chief of staff said. “Even those who are going, I would bet are only going for one day.”

That fits the description of Baldwin, who plans to spend most of this week on a statewide tour, with a stop at the convention Thursday “before returning to Wisconsin to continue the tour,” campaign spokesman Andrew Mamo said. The Harris-Walz ticket is planning to do a rally in Milwaukee Tuesday. Mamo said Baldwin, who has endorsed Harris and Walz, did not plan to attend because she had “prior engagements in northern Wisconsin.”