Sen. Mark Kelly rumored as possible Harris running mate

With President Biden ending his re-election bid , Arizona U.S. Sen. Mark Kelly is among the names circulating as a possible running mate with Vice President Kamala Harris , who Biden and other powerful Democrats quickly endorsed.

Why it matters: Kelly could bring a lot of advantages to a national ticket with Harris , including representing a swing state, a sympathetic personal story with his wife, former U.S. Rep. Gabrielle Giffords , and cred as a combat veteran and former astronaut.

The big picture: Speculation in various media reports was swirling around Kelly and a handful of other prominent Democrats, even before Biden made his decision Sunday.

Zoom in: A recent polling memo from BlueLabs Analytics listed Kelly as one of several Democrats polling better than Biden in a matchup against former President Trump.

The intrigue: Prior to Biden's announcement, Kelly consistently reiterated his support for Biden even as the movement to replace him as the Democratic nominee grew.

• Kelly's campaign did not respond Sunday to questions about whether he is now interested in the vice presidential position.

What they're saying: "It takes great humility to make the difficult decision that President Biden has made to not seek re-election, but that's the Joe Biden I know — someone who puts what he believes is best for his country above all else," Kelly posted on X yesterday afternoon .

• "I couldn't be more confident that Vice President [Kamala Harris] is the right person to defeat Donald Trump and lead our country into the future," he continued .

State of play: Other rumored Democratic running mates are Kentucky Gov. Andy Beshear, North Carolina Gov. Roy Cooper, Pennsylvania Gov. Josh Shapiro and Michigan Gov. Gretchen Whitmer.

Between the lines: If Kelly were elected vice president, he would have to resign his Senate seat, and Democratic Gov. Katie Hobbs would appoint a replacement.

• That appointee would have to run in a special election to serve out the remainder of the term, as Kelly did in 2020 when he ran against Republican Martha McSally, who was appointed to John McCain's seat.
• In that scenario, Arizona would have Senate races in every election from 2016 to 2030.

Editor's note: This story has been updated throughout.