Sinema's seat is a top 2024 target for Republicans looking to seize control of the upper chamber, where Democrats hold a tenuous 51-49 lead that includes Sinema — who dropped her affiliation as a Democrat after last year's midterm elections. 

Liberals want to knock Sinema out and Democratic Rep. Ruben Gallego (D) has already launched a bid to for the Senate seat.

The Trump-aligned Lake lost her gubernatorial bid last year and some Republicans think she could doom the party to defeat if she wins the GOP's Senate nomination.

But if it is a three-way race with Gallego, Sinema and Lake, few are entirely sure how it would turn out.

"Arizona is going to be the focal point again," said one GOP consultant, noting how close the battleground state came during the 2020 presidential race. "I know that everybody talks about Ohio, West Virginia and Montana as the keys for Republicans to take back the Senate. But Arizona is very deep in that mix."