Benjamin Netanyahu’s decision to assassinate Hassan Nasrallah, the Hezbollah leader, capped an increasingly brazen sequence of escalatory moves that reflected the Israeli prime minister’s renewed confidence in Israel’s military strength as well as in his own ability to navigate and defy foreign criticism, analysts said.

Mr. Netanyahu’s authorization of the strike came a day after the United States, Israel’s main benefactor, called for a cease-fire between Israel and Hezbollah. It occurred minutes after foreign diplomats walked out of his speech to the United Nations General Assembly, protesting the conduct of Israel’s wars in Gaza and Lebanon. And it came amid growing pressure on judges at the International Criminal Court to order his arrest on war crimes charges.

Last October, Mr. Netanyahu canceled a similar attack against Mr. Nasrallah following American pressure to call it off and internal doubts about Israel’s ability to fight on two fronts in Gaza and Lebanon after its failure to prevent Hamas’s Oct. 7 attack on southern Israel. His popularity plummeted after the Hamas raid, with polls repeatedly suggesting that he would easily lose power if a snap election was called.

Nearly a year later, Mr. Netanyahu appears far less deterred by either foreign pressure or domestic frailty. Fighting in Gaza has slowed, allowing the Israeli military to focus on Hezbollah, while Mr. Netanyahu did not even consult with the United States before authorizing the strike on Friday, according to U.S. officials.

“King Bibi is back,” said Nachman Shai, a former cabinet minister, referring to Mr. Netanyahu by his nickname. “If you compare Bibi now to Bibi 10 months ago, he’s a different person. He’s full of confidence.”