Sen. Jon Tester, D-Mont., is skipping the Democratic National Convention in Chicago this month when the party will rally around Vice President Kamala Harris as the Democratic presidential nominee, opting to stay in Montana ahead of a tight race to keep his Senate seat. 

A spokesperson for the longtime Montana Democrat told Fox News Digital that Tester "plans to spend his August farming and meeting face to face with Montanans."

Harris, who formally became the Democratic nominee for president last week, has yet to receive Tester's endorsement. 

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Jon Tester, Kamala Harris

Tester won't be attending the Democratic National Convention. (Getty Images)

When asked about a potential endorsement last week, he told Fox News' Kelly Phares, "We're working on my race right now, focused totally on that."

"We're going to win. And we'll deal with the presidential race when we have time to do that," he said. 

Despite his reluctance to get behind Harris, Tester reportedly had a direct role in pushing her to first run for Senate in 2016. Tester, who was chairman of the Democratic Senatorial Campaign Committee (DSCC) at the time, recruited and encouraged the now-vice president to run for Senate in California, according to the Los Angeles Times

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Sen. Jon Tester

Tester called on Biden to suspend his campaign last month. (Anna Moneymaker)

Tester's decision not to attend the DNC comes after Sen. Sherrod Brown, D-Ohio, who is in a similarly vulnerable position in his race, revealed he wouldn't be going to the convention in a recent interview. "I'm not going to the convention. I often skip conventions," he told CNN

Both Tester and Brown's races are rated as "Toss Ups" by non-partisan political handicapper the Cook Political Report. Races for Senate in Nevada and Michigan are also in the category. 

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Sen. Sherrod Brown, D-Ohio

Brown's race is also a "toss up." (Tom Williams/CQ-Roll Call, Inc via Getty Images)

The two incumbent Democrats also each officially called on President Biden to step aside last month, contributing to the pressure that ultimately pushed him to end his campaign. 

Fellow vulnerable Democratic Sens. Jacky Rosen of Nevada, Tammy Baldwin of Wisconsin, and Bob Casey of Pennsylvania, did not provide comment to Fox News Digital when asked if they would attend the DNC. 

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Jon Tester, Tim Sheehy

Sen. Jon Tester and Republican Montana Senate candidate Tim Sheehy. (Kevin Dietsch/Louise Johns)

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The apparent lack of interest or enthusiasm to attend the DNC is in stark contrast with their Republican opponents and the Republican National Convention, which took place last month. 

Republican candidates, including former Navy SEAL Tim Sheehy, running in Montana, retired Army Captain Sam Brown, running in Nevada, veteran Dave McCormick, running in Pennsylvania, former Rep. Mike Rogers, running in Michigan, and businessman Eric Hovde, running in Wisconsin, all attended the RNC. Each man also delivered remarks at the convention. 

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