Republicans win majority in the Senate, flipping control of upper chamber, CBS News projects

More than two weeks after Election Day, incumbent Sen. Bob Casey conceded in the U.S. Senate race in Pennsylvania to Republican challenger Dave McCormick. 

In an email from his campaign, Casey, a Democrat, said he called McCormick to congratulate him on his win in the race. 

"As the first count of ballots is completed, Pennsylvanians can move forward with the knowledge that their voices were heard, whether their vote was the first to be counted or the last," the email said in part. 

McCormick followed up with a statement thanking Casey, saying he had "dedicated his career to bettering our commonwealth."

A recount for the race was automatically triggered because the unofficial vote tally was within a 0.5% margin. CBS News has projected the race for McCormick. 

Read more from CBS News Philadelphia.

Pennsylvania's top election official announced Wednesday that the unofficial results in the Pennsylvania Senate race have triggered a statewide recount, as the race remains the sole Senate contest outstanding.  

The announcement comes as Sen. Bob Casey, the Democratic incumbent, has not conceded the race, although his challenger, Dave McCormick, attended orientation for senators-elect in Washington this week. Both parties are keeping close eyes on the tight race, which CBS News characterizes as leaning toward Republicans and could add to their incoming majority in the upper chamber. 

Under Pennsylvania law, races within a 0.5% margin trigger a statewide recount. Counties must begin the recount by Nov. 20. 

Read more from CBS News Philadelphia here. 

With the projected victory, Rep. Ruben Gallego is set to become the first Latino senator to represent Arizona. Gallego's victory over Trump-backed Republican Kari Lake was a hard-fought win for Democrats, who fell short of holding their narrow majority in the Senate. Gallego, the son of immigrant parents, is a Marine veteran and Harvard graduate who has served in the House since 2015.

Sen. Jacky Rosen's projected victory over Republican challenger Sam Brown marks a key win for Democrats, who were fighting to hold onto the Nevada seat while fending off challenges from Republicans across a number of states. Rosen, in her first reelection bid, was leading in the polls heading into Election Day, but the state has historically been difficult to poll and was home to one of the closest Senate races in the country in 2022.  

The Pennsylvania Senate race between Sen. Bob Casey and Republican challenger Dave McCormick is now considered to be leaning to McCormick, CBS News estimates. About 98% of the vote is in.

"Yesterday, the vote margin shrunk by 50,000 votes and this race is now within half a point, the threshold for automatic recounts in Pennsylvania," a spokesperson for Casey's campaign said Thursday, CBS News Philadelphia reported.

Rep. Elissa Slotkin is projected to beat former GOP Rep. Mike Rogers for the seat long held by Democratic Sen. Debbie Stabenow, who announced plans to retire. Michigan hasn't elected a Republican to the Senate in three decades, but this year's contest was considered among the most competitive of the cycle. Slotkin, a former CIA officer, has represented Michigan's 7th district in the House since 2019.

Sen. Tammy Baldwin's projected victory, securing a third term in the Senate, is a key win for Democrats in Wisconsin. Republican challenger Eric Hovde had hoped to flip the seat, but Baldwin, the first openly LGBTQ+ senator in history, has a long history of support from rural voters in the state, winning in Trump-aligned areas despite her progressive politics. 

Senate Minority Leader Mitch McConnell praised the successes of Senate Republicans across the country Tuesday night, as well as the massive fundraising efforts that funneled their wins, with Republicans projected to take back the Senate. It's still not clear which party will have control of the House.

McConnell said Republican control of the Senate will help "control the guardrails" of the nation.

"I think one of the most gratifying results of the Senate becoming Republican, the filibuster will stand, there won't be any new states admitted that give a partisan advantage to the other side, and we'll quit beating up the Supreme Court every time" the court makes a decision people don't like, McConnell said.

McConnell is set to address reporters Wednesday morning after a strong showing for Republican candidates on election night that secured a GOP majority in the chamber. McConnell, the longest-serving Senate leader in history, announced earlier this year that he would step down as Republican leader after the election, welcoming in the "next generation of leadership."

Tim Sheehy's projected victory over three-term Democratic incumbent Sen. Jon Tester helped Republicans build a GOP majority in the upper chamber.

Although Tester fended off previous challenges as a moderate in deep-red Montana, shifting demographics in the state enhanced the pickup opportunity for Republicans.

Experts say the state saw an influx of new residents, made up largely of Republicans, which posed trouble for the only Democrat serving in statewide office. Tester was among the final Democratic holdouts in the Great Plains, and in red states more broadly. 

Sen. Deb Fischer's projected victory in the red state is an outcome that seemed all but guaranteed just months ago, but then independent challenger Dan Osborn started gaining in the polls, teeing up a dramatic final sprint in the Cornhusker State. A surge of funding for Osborn, a Navy veteran, mechanic and union leader, forced Republicans to redouble their efforts in a race they'd expected to be an easy win. This will be Fischer's third term in the Senate.

Curtis' projected victory comes after Sen. Mitt Romney, once the Republican nominee for president, opted not to seek reelection. Curtis, who has represented Utah in the House since 2017 and formerly served as the mayor of Provo, Utah, beat out a more conservative Trump-endorsed candidate in the primary. 

Kaine was first elected in 2012, after serving as the state's governor. His opponent, Hung Cao, was aiming to become the first Republican to be elected to the Senate in Virginia in more than two decades.

With the projected victory, Ricketts will fill the remaining two years of former Sen. Ben Sasse's term. Ricketts, a Republican, was appointed to the Senate in 2023 upon Sasse's resignation to become president of the University of Florida.

Schiff's projected victory comes after a lengthy campaign for the seat long held by the late Sen. Dianne Feinstein. Schiff, 64, who currently represents California's 30th district in the House, rose to national prominence during the first impeachment trial against President Donald Trump, when he served as lead prosecutor. Schiff had the backing of former House Speaker Nancy Pelosi, a behemoth in California politics.  

Klobuchar, a Democrat, has been in the Senate since 2007. She sought the Democratic presidential nomination in 2020. 

In a big pickup for Republicans, businessman Bernie Moreno is projected to defeat three-term Democratic Sen. Sherrod Brown, flipping a key Senate seat for the GOP. Moreno, a Trump-backed Republican who has embraced election denialism, overcame criticism for legal troubles related to his automotive business. Brown was the sole remaining Democrat holding statewide office in the Buckeye State.

Cantwell, a Democrat, has been in the Senate since 2001. 

With a particularly favorable map this year for the GOP, CBS News now rates control of the Senate as leaning toward Republicans. As of 11:30 p.m. ET, Republicans have projected victories in 47 states, eyeing at least two more safe victories and possible flips in a handful of other states. 

Heinrich, a Democrat, has been in the Senate since 2013. 

CBS News estimates the Ohio Senate race leans toward Republican Bernie Moreno, as Sen. Sherrod Brown fights to hold onto his seat in the Buckeye State. Ohio is a top target for Republicans, seeking to gain a majority in the Senate. 

Kim's projected victory comes after former Sen. Bob Menendez's conviction and subsequent resignation earlier this year. Kim, a 42-year-old who has represented New Jersey in the House since 2019, is set to become the first Korean-American senator in history. 

Hawley, a Republican, has been in the Senate since 2019. 

Sen. Ted Cruz is projected to win reelection for a third term, ending Democrats' hopes for an upset in the Lone Star State. No Democrat has won a statewide election in Texas since 1994, and the challenge by Rep. Colin Allred, a former linebacker for the Tennessee Titans and civil rights attorney, ultimately fell short. 

Barrasso, a Republican, has been in the Senate since 2007.

Prince George's County Executive Angela Alsobrooks' projected victory over popular former Gov. Larry Hogan, a Republican, came after a challenging race for Democrats in normally deep-blue Maryland. But Hogan's message of working across the aisle for Marylanders appeared to fall short, as Alsobrooks emphasized that despite his bipartisan framing, Hogan could help hand control of the Senate to the GOP.

Wicker, a Republican, has been in the Senate since 2007.

Cramer, a Republican, has been in the Senate since 2019. 

Gillibrand has been in the Senate since 2009. She sought the Democratic nomination for president in 2020. 

In another blue wall state, Democratic Sen. Tammy Baldwin is fighting to hold onto control of her seat, facing a challenge from Republican Eric Hovde. Hovde, a businessman, is among a number of Republican Senate candidates recruited in part for their ability to fund their own campaigns this cycle, and is looking to oust the long-time senator who made history as the first openly LGBTQ senator. 

Democratic Rep. Colin Allred is aiming to unseat Republican Sen. Ted Cruz in red Texas, in a bid once considered a long shot that has appeared more competitive in recent weeks. Allred is a former linebacker for the Tennessee Titans who came to Congress after working as a civil rights attorney. No Democrat has won a statewide election in Texas since 1994.

Rep. Lisa Blunt Rochester's projected victory makes her the first Black woman elected to represent Delaware in the Senate, and the third elected to the Senate overall. The outcome comes after longtime Sen. Tom Carper announced his retirement. Blunt Rochester is currently Delaware's sole representative in the House. 

Democratic Rep. Elissa Slotkin and former Republican Rep. Mike Rogers are fighting to replace Sen. Debbie Stabenow in the Senate, after the longtime senator announced her retirement. The race is among a handful that are key to determining control of the chamber, as Republicans look to build a majority with wins in the blue wall states and beyond. 

Democratic Rep. Ruben Gallego and Republican Kari Lake are facing off in battleground Arizona for Sen. Kyrsten Sinema's seat in a race among a handful that are key to determining control of the Senate. Gallego, a progressive lawmaker and former Marine, has been leading in the polls leading up to Election Day.

Murphy, a Democrat, is projected to win his third term in the Senate, where he serves on the Appropriations, Foreign Affairs, and Health, Education, Labor and Pensions committees.

Whitehouse, a Democrat, has been in the Senate since 2007.

Republican Sen. Blackburn has been in the Senate since 2019. 

The Pennsylvania Senate race is among a number that Democrats are fighting to hold onto this cycle. In the Keystone State, Republican Dave McCormick is working to unseat Sen. Bob Casey, who's been in the Senate since 2007. Casey has widespread name recognition in battleground Pennsylvania, but the race has appeared to tighten in recent weeks between the longtime senator and former chief executive of a major hedge fund. 

Warren has been in the Senate since 2013. She sought the Democratic nomination for president in 2020. 

The projected victory for Scott, who's been in the Senate since 2019, comes as Democrats had eyed the state as a possible pickup opportunity. 

Sanders, an independent who caucuses with Democrats, has been in the Senate since 2007. 

The Ohio Senate race, which is among a number of races considered key to control of the upper chamber, is considered a toss up as polls close Tuesday night. Democratic Sen. Sherrod Brown's seat is a top target for Republicans looking to build a majority, as Republican Bernie Moreno vies for the seat.

Republican Jim Justice, the current governor of West Virginia, has won the state's Senate race, flipping the seat held by Joe Manchin. Manchin chose not to seek reelection and had changed from a Democrat to an Independent.

Jim Banks, a Republican, currently represents Indiana in the House, and he sought the Senate seat after Sen. Mike Braun opted to seek the governorship in Indiana.

Control of the Senate is up for grabs as Democrats look to defend their narrow majority, facing serious headwinds with few pickup opportunities — and ample room for the GOP to grow. 

Democrats currently have a 51-49 majority in the chamber. But Sen. Joe Manchin's decision to leave Congress all but guaranteed Republicans will flip his seat in deep-red West Virginia, and Republicans have opportunities in several other states that will determine control of the upper chamber.  

Republicans last won a majority in the Senate in 2018, before Democrats went on to secure a narrow majority in the two most recent elections. And control of the upper chamber has major implications for the new administration — either bolstering the president's agenda, or serving as a blockade for the opposing party. 

One-third of the chamber is in play in the 2024 cycle. Some of those 34 seats are considered safe for one party or the other, but a number of races are highly competitive or likely to flip. Control of the Senate will come down to the outcomes in nearly a dozen races.

Read on for more about the 11 key Senate races to watch. 

Sen. Sherrod Brown — the only Democrat holding statewide office in Ohio — is fighting to hold onto the seat he first won in 2006, as businessman Bernie Moreno, a Trump-backed Republican who has embraced election denialism, makes a play for the seat in what has been among the most expensive races this cycle. The Cook Political Report rates the race as a toss-up. 

Read more about the Ohio Senate race here.

In Michigan, former Republican Rep. Mike Rogers and Democratic Rep. Elissa Slotkin are vying for Sen. Debbie Stabenow's long-held seat in the upper chamber as Stabenow prepares to retire. Michigan hasn't elected a Republican to the Senate in three decades, but this year's contest is considered among the most competitive of the cycle, with the Cook Political Report rating the race as a toss-up. 

Prince George's County Executive Angela Alsobrooks, a Democrat, and former Maryland Gov. Larry Hogan, a Republican, are facing off in a race that's grown unexpectedly competitive in deep-blue Maryland, as the two look to replace Sen. Ben Cardin. A victory by Hogan would mark the first time a Republican has won a Maryland Senate seat in more than four decades. 

Read more about the Maryland Senate race here.

Democratic Sen. Jacky Rosen is looking to hold onto her seat in her first reelection bid, facing off against Sam Brown, a businessman and former Army captain. Nevada was home to one of the closest Senate races in the country in 2022, and although Republicans haven't won a Senate race in the Silver State since 2012, they flipped the governor's mansion in the last election, suggesting that this seat could be in play for the GOP. 

Read more about the Nevada Senate race here. 

Once considered a long-shot Democratic bid in the red state, Rep. Colin Allred has launched a formidable challenge against Sen. Ted Cruz, who has held the seat since 2013. No Democrat has won a statewide election in Texas since 1994, and the Cook Political Report rates the race as lean-Republican. But Texas remains among Democrats' best pickup opportunities in the upper chamber. 

Read more about the Texas Senate race here.

Democratic Rep. Ruben Gallego and Republican Kari Lake are duking it out for the seat held by Sen. Kyrsten Sinema, a Democrat-turned-independent who isn't seeking reelection. The Cook Political Report rates the race as leaning toward Democrats, as Gallego, a progressive lawmaker and former Marine, has worked to court voters in the middle, and Lake, who lost a hard-right bid for governor in 2022, has tried to do the same. 

Read more about the Arizona Senate race here. 

Considered among the most endangered Democrats this cycle, Sen. Jon Tester is fighting to keep the Senate seat he's held for nearly two decades against a challenge from businessman and former Navy SEAL Tim Sheehy. Although Tester has fended off previous challenges as a moderate in deep-red Montana, the state's shifting political dynamics have Republicans feeling optimistic about their pickup opportunity in the Big Sky State. 

Read more about the Montana Senate race here. 

Republican Dave McCormick is working to unseat Democratic Sen. Bob Casey, who's been in the Senate since 2007, in battleground Pennsylvania. McCormick, a combat veteran and former chief executive of a major hedge fund, is facing off against an institution in the Keystone State in Casey. But the race has appeared to tighten in recent weeks, and The Cook Political Report considered the race a toss-up. 

Read more about the Pennsylvania Senate race here. 

Democratic Sen. Tammy Baldwin is seeking a third term in the Senate, facing a challenge from Republican Eric Hovde in the Badger State. The businessman with deep pockets is one of a number of Republican Senate candidates recruited in part for their ability to fund their own campaigns this cycle. Baldwin has a long history of courting rural voters in the state, previously winning in counties that voted for Trump. The Cook Political Report rates the race as a toss-up. 

Read more about the Wisconsin Senate race here. 

A challenge from independent Navy veteran and union leader Dan Osborn has made for a surprisingly competitive race as Republican Sen. Deb Fischer seeks her third term. Osborn has received an onslaught of outside funding, forcing Republicans to redouble their efforts in a race that had been thought to be an easy win for Fischer. The Cook Political Report rates the race as likely Republican. 

Read more about the Nebraska Senate race here. 

Senate Democrats have all but ceded Sen. Joe Manchin's seat to Republicans after he announced he wouldn't seek reelection in the red state. Democrat Glenn Elliott, a former mayor of Wheeling, West Virginia, is facing off against current Republican Gov. Jim Justice, who is almost guaranteed a win in the Mountain State. The Cook Political Report rates the race as solid Republican.