Last week Senate Majority Leader Chuck Schumer insisted on holding doomed litmus-test votes on a federal election overhaul and filibuster reform. This damn-the-torpedoes strategy emboldened progressive attacks on the party’s centrists and exposed Democrats like Arizona Sen. Mark Kelly. He is up for re-election this year in a seat crucial to the Democratic majority and has been strategically quiet on big progressive issues.

Now, thanks to Mr. Schumer, Mr. Kelly has been forced to go on record as voting for an agenda that holds little appeal to moderate Arizona voters. Call it a bull’s-eye for the circular firing squad.

Meantime, progressive hatred for Arizona’s other senator, Kyrsten Sinema, has intensified. Rep. Ruben Gallego claims to have received “a lot of encouragement” from donors, unions, and elected officials for a potential 2024 primary challenge to Ms. Sinema. The results of an early December poll of 800 Arizona voters by the Moderate PAC show that Mr. Gallego would win such a primary by 12 percentage points. But 54% of Arizona general-election voters prefer a moderate and centrist U.S. Senate candidate, while only 23% prefer a progressive candidate. Ms. Sinema leads in a head-to-head contest with a generic Republican by 6 points, 35% to 29%. Mr. Gallego would struggle in a general election. It’s safe to assume Mr. Gallego is seeing similar data.