Republicans are all but guaranteed to pick up at least one seat, putting even more pressure on Democrats to win seven other highly competitive races, including two in red states.

Senate Democrats face a grueling and narrow path to maintain their slim 51-49 majority this fall, as they prepare to defend 23 seats across the United States, many of them in purple and red states.

With Sen. Joe Manchin III (I-W.Va.) retiring, Republicans are all but guaranteed to pick up at least one seat in that ruby red state, putting even more pressure on Sens. Sherrod Brown (D-Ohio) and Jon Tester (D-Mont.) to defy political gravity once again in their red states and win reelection. Only 11 Republican-held seats are up for election in November. If Republicans win those races as expected and flip just one state, the Senate will be tied 50-50 with deciding votes made by the new vice president. If they flip two seats, Republicans will win back Senate control no matter who is in the White House.

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