A trio of Democrat senators who were all elected during the blue-wave 2006 midterm cycle lost their re-election bids this week in a devastating blow to the party as the GOP regains control of the Senate. 

Pennsylvania Sen. Bob Casey, Ohio Sen. Sherrod Brown and Montana Sen. Jon Tester have served as Democrat stalwarts since they were sworn in 2007, but they watched their Senate careers end this week as they faced high-stakes challenges from Republicans. 

Fox News projected on Wednesday that the Republican Party flipped the Senate red, holding 53 seats as of Thursday afternoon. 

Sen. Bob Casey

Pennsylvania Sen. Bob Casey was projected to lose his high-stakes race against Republican challenger Dave McCormick on Thursday afternoon as Pennsylvania officials waded through votes in the razor-thin race. McCormick received 48.95% of the vote to Casey’s 48.49%.

The Casey name has deep roots in Pennsylvania, not only from the longtime Democrat senator but also his father, Bob Casey Sr., who served as the Keystone State’s governor from 1987 to 1995 after years of serving in various other elected roles. 

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Casey Jr. launched his first Senate campaign in 2005, working to unseat Republican Sen. Rick Santorum and flip the seat blue. Bolstered by his father’s wildly popular legacy and winning platform, Casey Jr. sailed to victory in the 2006 election, holding onto the seat for nearly 18 years.

Trump-endorsed Dave McCormick launched his Senate campaign to unseat Casey this cycle and officially declared victory in the race on Thursday as certain Pennsylvania jurisdictions continued counting votes after experiencing some voting hiccups on Tuesday.

McCormick portrayed Casey as an out-of-touch longtime politician with close ties to the Biden-Harris administration who put D.C. politics ahead of advocating for policies that benefited Pennsylvanians and voters nationwide.

Sen. Sherrod Brown

Ohio Democrat Sen. Sherrod Brown, who has served in the Senate since 2007 and has been in politics for half a century, was considered one of the most vulnerable incumbents heading into Tuesday night, and he ultimately fell to his GOP challenger as Trump carried Ohio by more than 10 points.

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Brown, who lost to Cleveland area businessman Bernie Moreno by about four points, attempted to highlight areas where he disagreed with President Biden but was ultimately weighted down by a voting record that was nearly 100% in line with the president and a climate of opposition to illegal immigration and a difficult economy.

“This is a disappointment but is not a failure,” Brown said in his concession speech. “It will never be wrong to fight for organized labor, it will never be wrong to fight for the freedom of women to make their health care decisions, it surely will never be wrong to fight for civil rights and human rights.”

Sen. Jon Tester

Three-term Sen. Jon Tester, D-Mont., lost the 2024 Montana Senate race, but his long-held position is remembered by his ability to hold a blue seat for nearly two decades despite the state’s significant shift to red.

Tester, a dirt farmer from Big Sandy, was first elected to the Senate in 2006, ousting three-term former Republican Sen. Conrad Burns for the Big Sky State seat he would go on to hold for the next 18 years.

Tester’s win notably solidified Montana as a dominantly blue state that year, with two Democrat senators and a Democrat governor. Tester went on to win a second term in 2012 despite being on the ballot with then-Republican presidential candidate Mitt Romney, who won Montana’s electoral votes that year.

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The state saw a significant shift red in 2014 when Republican Sen. Steve Daines flipped one of the long-held Democrat Senate seats for Republicans, the first of several seats that would eventually turn to the GOP.

However, despite President-elect Trump winning Montana by about 20 points in 2016, Tester successfully secured a third term in 2018. Tester broke the mold of many Democrats in Washington, D.C.: a rural American farmer who championed protecting the Second Amendment and funding law enforcement.

But as Tester sought a fourth term in the state, he faced an increasingly red electorate.

The Democrat’s standing in the state came to an end this cycle after former Navy SEAL Tim Sheehy, a Republican, ousted him in one of the most closely watched Senate races of the 2024 cycle.

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