The special election on Tuesday in Arizonas 7th Congressional District is widely expected to narrow the GOPs already slim majority in the U.S. House.Democrats enjoy a nearly two-to-one voter registration advantage over Republicans in southern Arizona's left-leaning congressional district, which stretches from Yuma to Tucson and includes almost the entire length of the state's border with Mexico.Democratic Pima County Supervisor Adelita Grijalva, the daughter of the late congressman, is facing off in the special election against small business owner and contractor Daniel Butierez, the Republican nominee, with two third-party candidates also on the ballot."In Congress, I commit to fight Trumps cruel agenda, like the Big Ugly Bill that took away coverage from nearly 383,000 Arizonans and 142,000 children," Grijalva pledged in a social media post, as she took aim at President Donald Trump, congressional Republicans and their sweeping domestic policy measure.TRUMP NOT ON BALLOT BUT FRONT-AND-CENTER IN 2025 ELECTIONSButierez, meanwhile, has been promoting himself as the change candidate in a district controlled by Democrats since the seat was created over two decades ago."This is your chance to actually get a Representative who will represent everyone. If you vote we win, if you don't only the radicals will have representation," he wrote on X.HEAD HERE FOR FOX NEWS' 2025 ELECTION COVERAGEThe winner will serve out the remaining 15 months of the term of the elder Grijalva, who died in March following complications from cancer treatment.Republicans currently control the House 219-213, with three vacant seats.Besides Arizona's 7th Congressional District, there's also a vacancy in the Texas 18th Congressional District, a heavily Democrat-dominated district in Houston, following the March death of Democratic Rep. Sylvester Turner. The special election to fill the seat will be held on November 4, which is Election Day 2025.Tennessee's 7th Congressional District, a right-leaning seat where Republican Rep. Mark Green stepped down in July to take a job in the private sector, is also currently vacant. The special election to fill the seat will be held on December 2.In Arizona, the younger Grijalva, thanks in part to her family name and her support from national progressive rock stars Sen. Bernie Sanders of Vermont and Rep. Alexandria Ocasio-Cortez of New York, grabbed over 60% of the primary vote this summer in a five-candidate showdown.Progressive activist and social media influencer Deja Foxx came in a distant second.Grajalva, if elected, would become Arizona's first Latina in Congress.Butierez, who as the 2024 GOP congressional nominee lost to the elder Grijalva while Trump narrowly carried the southwestern battleground state at the top of the ballot, easily won this summer's Republican primary in the special election.While Trump carried Arizona last year after losing it in 2020, 2024 Democratic presidential nominee and then-Vice President Kamala Harris won the district by 23 points.