Democratic vice presidential hopeful Gov. Tim Walz (Minn.) is rallying voters in the critical swing state of Arizona on Wednesday evening. Earlier in the day, Walz campaigned in the Phoenix area alongside Rep. Ruben Gallego (D-Ariz.), who is running to replace retiring independent Sen. Kyrsten Sinema. Gallego and his GOP challenger, Kari Lake, will engage in a debate late Wednesday. The Hill/Decision Desk HQ's aggregate of polls shows the presidential nominees, Vice President Harris and former President Trump, locked in a tight race in the Grand Canyon State, with the election less than a month away. Walz's remarks in Tucson, Ariz., come just hours after his GOP opponent, Sen. JD Vance (R-Ohio), held a campaign event in the same city. The event is scheduled to begin at 6:30 p.m. EDT. Watch the live video above.