Benny Gantz, a relative centrist and one of Netanyahu's principal political rivals, arrived in Washington on Sunday afternoon. He's slated to meet on Monday with Vice President Kamala Harris and National Security Advisor Jake Sullivan. On Tuesday, he'll talk with Secretary of State Antony Blinken, and he will also meet senior Congressional leaders during his stay. There's some possibility that President Biden will opt to join one of the White House sessions, sources tell Israeli outlet Ynet News. 

The first Netanyahu heard of the trip was when Gantz called him on Friday to spring the news and ask for Netanyahu's input about what to communicate to American officials, the Times of Israel reports. The call grew heated, with Netanyahu scolding Gantz, and telling him that "The State of Israel has only one prime minister."   

The prime minister's office doesn't consider Gantz's trip to be an official one, since it's happening without Netanyahu's permissions. Consistent with that view, Netanyahu ordered Israel's US ambassador, Michael Herzog, to refrain from providing any assistance to Gantz during his visit. He also blocked government financing of Gantz's travel, which will take him to the United Kingdom next. 

Four days after the Oct. 7 Hamas invasion of southern Israel, Gantz joined Netanyahu in forming an emergency unity government. Nearly five months into the war, Netanyahu is embattled and deeply unpopular. Many Israelis say he's to blame for the Israel Defense Forces being caught off-guard by the Hamas attack. Families of Israelis taken hostage have mounted protests demanding Netanyahu approve a prisoner swap.