They share a podium — and a mutual frustration. White House press secretary Karine Jean-Pierre and the National Security Council's John Kirby frequently split the podium at media briefings, but behind the scenes their relationship is fraught with tension, White House sources tell Axios.

Why it matters: As President Biden heads into a tough re-election campaign, his top-ranking spokespeople are at odds while navigating a situation in which there's one press secretary in name but two in practice — one for domestic policy, the other for foreign policy.

Zoom in: Some of the tension stems from how much time each gets at the podium each day.

Kirby — a Biden favorite who has become the public face of the administration's response to the Israel-Hamas war — has told people he'd like to be White House press secretary one day.

Jean-Pierre has told people she plans to stay in the job through the election and beyond if Biden wants her — and that he has asked her not to leave.

A White House official told Axios that Kirby never volunteers that he would like to be press secretary.