Four more Republican-held House seats are joining The Cook Political Report's list of "toss-up" races, the election handicapper announced Wednesday.

Among the races moving over to the "toss-up" column: California's 45th District, held by Rep. Mimi Walters; New Jersey's 3rd District, held by Rep. Tom MacArthur Thomas (Tom) Charles MacArthurRepublican David Richter wins NJ primary in race to challenge Rep. Andy Kim What to watch in New Jersey's primaries on Tuesday Republicans plot comeback in New Jersey MORE; and Pennsylvania's 10th District, held by Rep. Scott Perry Scott Gordon PerryOn The Trail: How Nancy Pelosi could improbably become president GOP lawmaker: Systemic racism doesn't exist and there's 'more to the story' of Floyd's death We're united in an effort to end the FDA's dog testing mandate MORE.

North Carolina's 9th District, which is currently represented by outgoing Rep. Robert Pittenger Robert Miller PittengerBottom Line North Carolina reporter says there could be 'new crop' of GOP candidates in 9th Congressional District race North Carolina board calls for new election in contested House race MORE (R), was also moved to the "toss-up" category, Cook reported. Pittenger was defeated by pastor Mark Harris in his primary earlier this year, but Republicans are intent on keeping the seat in GOP hands.

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The latest race-rating movements are welcome news for Democrats, who are working to stage a comeback in dozens of GOP-held congressional districts in a bid to retake the House.

But Cook's changes weren't all bad news for Republicans. Florida's 26th District, currently represented by Rep. Carlos Curbelo Carlos Luis CurbeloGOP wants more vision, policy from Trump at convention Mucarsel-Powell, Giménez to battle for Florida swing district The Memo: GOP cringes at new Trump race controversy MORE (R), was moved out of the "toss-up" column to "lean Republican," meaning the race remains competitive but with a GOP advantage.

Curbelo has widely been seen as one of the most vulnerable representatives from Florida. Democratic presidential nominee Hillary Clinton Hillary Diane Rodham ClintonFox News poll: Biden ahead of Trump in Nevada, Pennsylvania and Ohio Trump, Biden court Black business owners in final election sprint The power of incumbency: How Trump is using the Oval Office to win reelection MORE carried the district by 16 points over President Trump Donald John TrumpSteele Dossier sub-source was subject of FBI counterintelligence probe Pelosi slams Trump executive order on pre-existing conditions: It 'isn't worth the paper it's signed on' Trump 'no longer angry' at Romney because of Supreme Court stance MORE in 2016, and former President Obama beat out Republican nominee Mitt Romney Willard (Mitt) Mitt RomneyTrump 'no longer angry' at Romney because of Supreme Court stance GOP lawmakers distance themselves from Trump comments on transfer of power McConnell pushes back on Trump: 'There will be an orderly transition' MORE there by about 11 points in 2012.

He is widely expected to face Democrat Debbie Mucarsel-Powell in the general election in November.