Former Sen. Sherrod Brown of Ohio on Monday launched his 2026 bid to return to the U.S. Senate, following last year's bitter re-election defeat at the hands of now-Sen. Bernie Moreno."Standing up for workers. Treating everyone with dignity and respect. Working as hard as possible for the people of Ohio. I've tried to live my life by those principles. But these days that's not what's happening in Washingtonso I'm running for Senate," Brown said in a social media post as he highlighted his longtime working class and populist themes.Brown, who spent over three decades representing Ohio in the House and later the Senate, was highly recruited by top national Democrats, including Senate Minority Leader Chuck Schumer, who made two trips to the Buckeye state to try and convince Brown to run again.FOUR KEY SENATE SEATS REPUBLICANS AIM TO FLIP IN 2026 MIDTERMSBrown is seeking the seat held by Republican Sen. Jon Husted, the former Ohio lieutenant governor who was appointed in January to fill the seat left vacant when then Sen. JD Vance stepped down to become vice president in President Donald Trump's administration.SENATE DEMOCRATS LAND SOME BIG FISH IN BID TO WIN BACK MAJORITY IN 2026Husted has Trump's endorsement as he runs next year to fill the final two years of Vance's six-year term."I didnt plan to run for office again, but when I see whats going on, I know I can do something about it for Ohio," Brown said in a campaign launch video."Thats why Im running for Senate. Because even in these challenging times, I still believe if you stand up for workers, treat people with respect and always fight for Ohio, you can actually make a difference," he added.Schumer and Sen. Kirsten Gillibrand, chair of the Democratic Senatorial Campaign Committee (DSCC), argued in a statement that "no one fights harder for Ohio than Sherrod Brown. From securing Ohioans retirement and Social Security benefits to cracking down on fentanyl from China and Mexico, Sherrod will always do whats right for Ohioans."FIRST ON FOX: EX-SENATOR'S PAC SPLURGES ON LUXURY PERKSBut the National Republican Senatorial Committee (NRSC) accused Brown of being a "liberal sell-out" and pointed to his defeat in last year's election."Ohioans just rejected Sherrod Brown's radical agenda of allowing biological men to compete in women's sports, fueling mass illegal immigration, and failing to protect Ohio's good-paying manufacturing jobs," NRSC regional press secretary Nick Puglia claimed.And Alex Latcham, executive director of the Senate Leadership Fund, which is the top super PAC supporting Senate Republicans, charged that "Brown built his disgraceful career on the backs of hardworking Ohio families while he supported the woke Lefts agenda, including amnesty for criminal illegal immigrants, men in girls locker rooms, and sticking seniors with higher taxes. Ohioans gladly sent him packing last year, and theyll not hesitate to toss him aside again."Ohio was once a top general election battleground state, but has turned increasingly red over the past decade. Trump carried the state by 11 points over then-Vice President Kamala Harris. But Brown outperformed the top of the ticket, losing to Moreno by less than four points.Brown is the second top recruit Senate Democrats have landed this year as they work to try and win back the chamber's majority next year. The GOP currently holds a 53-47 majority in the Senate.Last month, former two-term Democratic Gov. Roy Cooper of North Carolina declared his candidacy in the 2026 race to succeed retiring Republican Sen. Thom Tillis.