2024 Election: Kari Lake, Mark Lamb running for GOP nomination in race to replace Sen. Kyrsten Sinema

PHOENIX - For this year's primary election, there's a lot of attention on who will be the Republican Party nominee for Arizona's open Senate seat: the incumbent for that seat, Democrat turned independent Kyrsten Sinema, is not running for re-election.

Sinema occupied the Senate seat as a moderate, and with her decision not to run for a second Senate term, it also means the seat could turn solidly progressive or conservative, depending on who wins in November.

Who's running for Sinema's seat?

The Democratic Party primary is uncontested, as Ruben Gallego is the only listed candidate in that primary. Gallego is currently a member of the U.S. House, representing Arizona's 3rd Congressional District. He is not running for re-election to that seat.

"I feel very excited and very good, because we are going to polling places, and we are talking to voters excited to vote, and it really tells you what’s going to happen in the general election," said Rep. Gallego.

On the Republican side, there are two major candidates in the GOP primary: Kari Lake and Pinal County Sheriff Mark Lamb.

According to a recent Noble Predictive Insights poll, Lake is leading Lamb 49% to 38% among Republicans. Lake also has the support of former President Donald Trump, who urged voters to back her in a telephone rally on Monday.

"So, we are going to work really hard, starting tomorrow, going back on the campaign trail in all parts of Arizona, and make sure we bring America first policies back to Washington, D.C., and back to America," said Lake.

"We feel great," Sheriff Lamb said. "We feel like we are in the driving seat. Take the polls out of it, and what we are hearing from people and what we are seeing is very different than what the polling and media are saying, so we feel very good about tonight."

Challenges lie ahead for the nominees

Barring any surprises, political experts expect a Lake-Gallego matchup in November, and each candidate will have to navigate challenges in the months ahead.

For Lake, the challenges lay with young voters and independents, and for Gallego, his challenge is defending Vice President and presumptive Democratic presidential nominee Kamala Harris’ stance and approach on the border.