Key points:

• Several key general election races are already taking shape after Tuesday’s primary election

• Incumbent candidates in competitive districts led their primary races after initial primary results

• Both Republican majorities in the state House and Senate are at stake this November with slim leads in each chamber

Arizona has one of the nation’s most closely divided state legislatures, with Republicans holding narrow majorities in both chambers.

While primary results are still being finalized ahead of the state’s official canvass on Aug. 6, candidates in a handful of competitive legislative districts have already advanced to the general election, where control of the Legislature will be decided in November.

For most legislative candidates, these primary races are effectively the decisive contests, as many districts heavily favor one party. Only a small number of swing districts are expected to be competitive in the general election, and even fewer featured contested primaries.

Republicans hold a 17-13 advantage in the Senate and a 33-27 advantage in the House. The last time Democrats held a majority in either chamber was in 1991, when Democrats held the Senate. The Senate was split evenly in 2001. Democrats last held the House in 1965.

Here are five races which could determine which party controls the Legislature in 2027:

Legislative District 2 Senate race

The crowded LD 2 Senate race could swing either way, as it remains one of the most competitive legislative districts in Arizona.

Incumbent Sen. Shawnna Bolick, R-Phoenix, took home the title in the 2025 legislative session for most bills signed and won the 2024 general election over former Democratic state Rep. Judy Schwiebert by more than 3 percentage points.

She faced Timothy Ferrara in this year’s primary. Ferrara, an information technology specialist and state Republican committeeman, argued that Bolick has lost touch with the voters.

Ferrara is running as a Clean Elections candidate and declared “the voters are my boss” during a one-on-one conversation in lieu of a debate with Bolick. After Thursday’s unofficial election results from the secretary of state’s office, Bolick led the race with 71% of votes to Ferrara’s 29%.

Two Democrats are also attempting to take on the Republican Senate primary winner in the district. Amelia Gallitano, a doctor, professor, research scientist and mother of two sons, challenged Daniel Toporek, a veteran and Arizona native.

During the LD 2 debate earlier this year, the two didn’t differentiate themselves much from each other except on data centers. Toporek said he wouldn’t pause new data center approvals, and instead, he’d make sure there’s legislation and law to ensure those profitable entities are producing their own power.

Gallitano said data centers create a lot of short-term jobs, but not long-term jobs, and added Arizona needs “real limits.” On Thursday, Gallitano led with about 77% of the vote, and Toporek received 23%.

According to the most recent voter registration records from the Secretary of State, Republicans have the advantage by about 10,991 active voters. Democrats recorded 34,760 voters while Republicans claimed 45,751. As for voters with no party designation, they claim 47,197 active voters.

Legislative District 4 Senate race

No primary challengers emerged in the Legislative District 4 Senate race, setting up a November showdown between incumbent Sen. Carine Werner, R-Scottsdale, and former Democratic Rep. Aaron Lieberman.

Lieberman, a business owner who helps bring electric vehicle charging stations to apartment complexes, was elected twice to the House and resigned in 2021 to make a what he called a “spectacularly unsuccessful” run for governor.

Werner defeated then-incumbent Democratic Sen. Christine Marsh by just under 4 percentage points in their 2024 race after Marsh represented the area for four years.

Republicans have a slightly larger voter presence in LD4, which covers north Scottsdale, Paradise Valley and north Phoenix. They lead with 66,152 active voters, while Democrats trail with 43,945. There are 55,812 voters with no party designation in LD4.

Legislative District 4 House race

The LD4 House race is another key battleground as Democrats try to take back some legislative seats after losing their Senate seat and a House seat in 2024.

Incumbent Reps. Matt Gress, R-Phoenix; and Pamela Carter, R-Scottsdale, face a Republican primary challenge from Sandra Christensen, a Paradise Valley Unified School District governing board member.

By Thursday, Gress and Carter led with 45% and 34% of votes to Christensen’s 21%.

The two Democrats challenging the Republican winners are Madison Elementary School District governing board member Karen Gresham and business owner Tammy Caputi.

Both women are running unopposed in the primary race, although Gresham was unsuccessful in running for the House in the district’s 2024 general election race by about a 2 percentage point loss to Carter.

Legislative District 13 House race

With House Majority Whip Julie Willoughby, R-Chandler, hoping to win her district’s Senate seat this November, the House race in the competitive Chandler district has no incumbent candidate and is wide open for both Republicans and Democrats.

Republicans took all three legislative seats in the district’s previous election, which helped expand the GOP majority in the House. But the district is considered highly competitive by the Arizona Independent Redistricting Commission. Former Democratic Rep. Jennifer Pawlik represented the area for six years before deciding not to seek re-election in 2024.

Rep. Jeff Weninger, R-Chandler, is running for Chandler mayor instead of seeking re-election to the House. The current Republican Chandler Mayor Kevin Hartke is running for the state House in LD13, along with Weninger’s wife, Janet Weninger, and fellow Republican Debra Schinke, who serves on the Chandler Citizens Police Review Board.

Through Thursday, Hartke and Janet Weninger led the primary race in the district with about 43% and 35% of votes over Schinke’s 22%, according to unofficial election results posted by the secretary of state’s office.

The Democratic candidates in the race, Rockee Armstrong and Jacob Weinberg, didn’t have primary opponents and will advance to the general election.

Republicans hold a 51,000 voter registration advantage over 38,000 registered Democrats in the district, but another 52,000 voters don’t have a party affiliation.

Legislative District 17 House race

While this district wasn’t considered to be competitive when Arizona’s legislative districts were redrawn, it has become a competitive district after Rep. Kevin Volk, D-Tucson, defeated former Republican Rep. Cory McGarr in an upset victory in 2024 as a single-shot candidate.

The district leans Republican and is considered by the redistricting commission to be outside its competitive range, but Democratic legislative candidates have seen close races in LD17 since 2022. Last election cycle, Sen. Vince Leach, R-Tucson, narrowly defeated the late Democrat John McLean by 2 percentage points in their race.

There are nearly 70,000 registered Republicans in the Pima and Pinal counties district. Almost 52,000 voters are registered as Democrats, and another 61,000 registered voters don’t have a party affiliation.

This year, Volk has a running mate with fellow Democrat Holly Lyon for the district’s two House seats. Rep. Rachel Keshel, R-Tucson, is running with Republican John Winchester to attempt to take back both seats.

All House candidates in the race will advance to the general election since no other candidates ran in the primary race.