Meet the new Hamas boss: As the Who might have sung, he’s the same as the old boss. The terror organization’s Gaza leader and architect of the October 7 attacks against Israel, Yahya Sinwar, on Tuesday was chosen to replace its politburo chief, Ismail Haniyeh, who was killed last week at Tehran.

Mr. Sinwar is the brain behind the October atrocities that launched a Mideast war now in its 10th month. As the official new political chief, he will replace Haniyeh and become the Hamas representative in the American-backed negotiations for a Gaza cease-fire and release of hostages.

Yet, Mr. Sinwar — who is widely believed to be hiding in a maze of Gaza tunnels, surrounded by dozens of hostages that he uses as human shields — has always had the final say on what conditions Hamas will, or will not, accept in a possible war-ending deal. He has also been considered a cunning and ruthless operator, and the hardest of Hamas hard-liners. 

Last week, the Israel Defense Force confirmed that on July 13 it killed the Gaza military chief, Mohamed Deif. Also last week, Haniyeh was killed while visiting Tehran. Two of the leadership’s survivors, Mr. Sinwar and his younger brother, Mohammed, are considered top targets, and many Israelis believe that unless they are eliminated the war will never end. 

“Yahya Sinwar is a terrorist who is responsible for the most brutal terrorist attack in history on October 7th,” the IDF spokesman, Rear Admiral Daniel Hagari, told Al Arabiya television Tuesday. “There is only one place for Sinwar, and that is beside Mohammed Deif and the rest of the October 7th terrorists. That is the only place we’re preparing and intending for him.”    

“We need to kill him,” a former prime minister, Naftali Bennet, told Fox News. “We need to defeat Hamas and have them release the hostages.” He suggested that for that purpose Israel would be willing to exile some leaders, “put them on a ship and get them out of Gaza.” 

For now, by officially crowning Mr. Sinwar political chief, Hamas is cutting the negotiations’ middleman, a role that until now was assigned to the Doha-based Haniyeh. Prior to his death, Mr. Sinwar communicated with Haniyeh, instructing him on every step of the cease-fire negotiations before relating them to Qatari and Egyptian negotiators.

Internally, Mr. Sinwar’s selection represents a complete takeover of the terror group by its Gaza-based, pro-Iran faction. The Egypt-born Haniyeh was also a member of that group, yet his life of affluence in fancy Doha hotels has turned many Gazans against him. Mr. Sinwar, in contrast, is either despised or admired by the Strip’s residents, but he is seen as one of their own. 

For days, though, the speculation among Hamas watchers has been that Khaled Mashal, who served as the organization’s political chief between 1996 and 2017, would return to the post after Haniyeh’s death. Mr. Mashal is considered closest to the Qatari regime, and has opposed Hamas’s ever-tighter relations with Iran, which both Haniyeh and Mr. Sinwar cultivated.  

In 1997, when Mr. Mashal was at Amman, Jordan, Israel injected him with a lethal poisonous substance. Yet, the Mossad agents were captured by the local police. In a deal for their release, Israel was forced to deliver an antidote that saved Mr. Mashal’s life. Despite his prominence, though, Mr. Mashal seems to have been overlooked in the latest leadership shuffle. 

The selection seems to have been haphazard, made as speculation regarding Haniyeh’s replacement grew over the region. On Monday a new name surfaced, apparently leaked by someone in the Hamas ranks: According to several Mideast reports, Abu Omar Hassan, also known as Mohamed Ismail Darwish, has been named as interim Hamas chief until an election for a permanent Haniyeh replacement is to be conducted next year. 

The name, though, was largely unknown. “I’ve been covering this beat for years and I never heard of him,” a Palestinian affairs analyst for Israel’s Kan news, Elior Levy, said. “So I asked sources in Gaza and the West Bank, and they never heard of him either. Nor did my Israeli intelligence contacts.” In other words, Mr. Levy said, “This sounds like a made-up person.”

The episode might indicate that Hamas could be less organized than widely portrayed. Or it could be that Mr. Sinwar has leaked it. Either way, the man who has spent years in Israeli prisons for organizing suicide bombings is now the unchallenged Hamas chief. Also, he has the backing of Iran’s Islamic Revolutionary Guards Corps. 

Yet, targeting by Israel could shorten the new boss’s tenure and deal a major blow to Hamas. Mr. Sinwar is “running the group from tunnels under Gaza while he is being hunted by Israel,” the Foundation for Defense of Democracies’s vice president for research, Jonathan Schanzer, writes on X. “Hamas is unraveling.”