Voters in Delaware will participate in the final state primary election in the United States before the November midterm elections on Tuesday. Polls open at 7am ET (12:00 GMT) and close at 8pm ET (0:00 GMT).

Delaware operates under a closed primary system, meaning only registered Democrats can vote in the Democratic Primary and only registered Republicans can vote in the Republican Primary. Primaries are only conducted if multiple candidates from the same party are vying for a single office; candidates running unopposed have already secured their spots in the general election.

Several key races are on the ballot, including nominations for US Senator, US Representative, and State Attorney General, all held by incumbents seeking re-election. Voters will also select nominees for the State Legislature and an open seat for State Treasurer. While control of the US Senate and House may hinge on close contests elsewhere, Delaware's congressional seats are widely expected to remain under Democratic control, reflecting the state's strong Democratic leanings since the 1990s.

In the race for the US Senate, incumbent Democratic Senator Chris Coons is seeking a third full term and faces three primary challengers: University of Delaware history Professor Jeff Appelhans, naval architect Mary Louve, and former business executive Eric Hansen. Hansen, who was the Republican nominee in 2024, is now running as a Democrat under the name "E. No-Trump Hansen." On the Republican side, former State Senator Michael Katz and US Army Reserve Colonel John Shulli are competing for the party's Senate nomination.

For the US House of Representatives, Democratic Representative Sarah McBride, the first openly transgender member of Congress, is unopposed in her primary bid for a second term as Delaware's sole representative. The Republican nomination to challenge McBride will be decided between Joseph Arminio, Earl Cooper, and John Whalen.

As of September 1, Delaware had approximately 808,000 registered voters, with about 331,000 registered as Democrats and 199,000 as Republicans. The state has a history of electing Democrats to federal office; Republicans have not won the governorship since 1988, a US Senate seat since 1994, or the US House seat since 2008.

The outcomes of these primaries will finalize the candidate lists for the November general election, setting the stage for contests that will shape the political landscape in Delaware and potentially influence the broader balance of power in Congress.

While Delaware's congressional races are not considered competitive for general election control, the primary contests offer insights into the internal dynamics of both major parties within the state as they prepare for the upcoming midterm elections.