Pointed at this by Taegan Goddard's Political Wire.
From NBCNews, emphasis added by me -
Head of Senate GOP campaign arm shows Republicans internal poll with Democrat leading in Arizona
At a closed-door meeting Tuesday, National Republican Senatorial Committee Chair Steve Daines showed fellow GOP senators an internal poll of a three-way Arizona Senate race that found Democratic Rep. Ruben Gallego leading with 41%, followed by Republican Kari Lake with 37% and independent Sen. Kyrsten Sinema with 17%, said a source familiar with the meeting.
Notably, Daines told Republicans that Sinema is currently pulling more votes from Lake than she is from Gallego, despite her longtime affiliation with Democrats before she became an independent last year.
Actually, the highlighted section may be an incorrect statement.
From the Political Wire post -
In a head-to-head matchup, Gallego leads Lake 49% to 44%.
Based on that, with Sinema in the race, Gallego is leading by 4%; with her not running, he's leading by 5%. Seems like that she's pulling votes from him, so the NRSC may be hoping that she runs for re-election. She's not going to win, but her presence helps Lake.
