Two Key Matchups Are Set in Arizona as Battle for House Control Heats Up

Primary elections in Arizona this week set the fields for two House races that could help determine which party wins control of Congress in November, as Democrats target two vulnerable Republican incumbents.

In Arizona’s Sixth District, which stretches from Tucson to the state’s border with New Mexico, Representative Juan Ciscomani overcame a primary challenge from Kathleen Winn. Ms. Winn had run to his right and argued that Mr. Ciscomani, who had the endorsement of former President Donald J. Trump, was too willing to work across the aisle with Democrats.

Mr. Ciscomani is now set for a November rematch of his 2022 contest with Kirsten Engel, a former state senator who lost two years ago by just 1.4 percent of the vote and ran unopposed in the Democratic primary on Tuesday.

Republican leaders in Congress celebrated Mr. Ciscomani’s primary win, and he indicated on social media that he intended to focus his general-election campaign on border security and inflation. Ms. Engel is on the Democratic Congressional Campaign Committee’s “Red to Blue” list of candidates whom the party has deemed most promising, and she has the backing of abortion rights groups.

The tighter competition was in the First District, in northeastern Phoenix and Scottsdale, where a crowded field of Democrats vied for the chance to face Representative David Schweikert. Amish Shah, a former member of Arizona’s House of Representatives, came out on top, with about 24 percent of the vote.

Mr. Shah beat a field that included Andrei Cherny, a former state party chair; Marlene Galán-Woods, a former broadcast journalist; and Conor O’Callaghan, an investment banker.

Mr. Schweikert won in 2022 by less than a percentage point.