Iowa Democrat Catelin Drey on Tuesday defeated Republican Christopher Prosch for an open state Senate seat, flipping the Republican-held seat and breaking the GOP's supermajority in the upper chamber for the first time in three years, according to unofficial results from the Woodbury County Auditor's Office.Drey secured 55% of the vote in the race to replace late Republican state Sen. Rocky De Witt, who died in June at the age of 66 after a battle with pancreatic cancer.This is the second time this year Democrats have flipped a Republican-controlled state Senate seat in Iowa, after Democrat Mike Zimmer defeated Republican Katie Whittington in a special election in January.4 KEY SENATE SEATS REPUBLICANS AIM TO FLIP IN 2026 MIDTERMS TO EXPAND THEIR MAJORITYDrey won a district President Donald Trump carried by more than 11 points last year, and the president won Zimmer's district by more than 20 points.Democrats have won several other special-election wins this year as the party hopes to build on the momentum leading into next year's midterm elections, when they'll attempt to flip the GOP majorities in the U.S. House and U.S. Senate.SENATE DEMOCRATS ARE FEVERISHLY RECRUITING TOP CANDIDATES TO WIN BACK MAJORITY IN 2026 MIDTERMS"Iowans are seeing Republicans for who they are: self-serving liars who will throw their constituents under the bus to rubber stamp Donald Trump’s disastrous agenda — and they’re ready for change," Democratic National Committee chair Ken Martin said in a statement."They are putting Republicans on notice and making it crystal clear: any Republican pushing Trump’s unpopular, extreme agenda has no place governing on behalf of Iowa families," he continued. "That's why all year long, Iowans have been electing Democrats ready to fight for working Iowans. Make no mistake: when Democrats organize everywhere, we win everywhere, and today is no exception."Drey’s victory breaks a Republican supermajority in the state Senate, giving Iowa Democrats more authority to stop GOP initiatives – including the ability to stop the governor's nominees, who require two-thirds support for confirmation. Fox News' Paul Steinhauser contributed to this report.