GAZA CITY — It's a strange semantic convergence. Both Israel and top Hamas security officials use the same adjective to describe Yahya Sinwar: "pragmatic." In February, the 55-year-old native of the Khan Younis refugee camp became leader of the armed Islamist movement that rules Gaza, while veteran Hamas leader Ismail Haniyeh was appointed head of the political bureau. But in the 10 months since, the spotlight has been shifted squarely onto Sinwar.

As the Egyptians' chosen intermediary, Sinwar has put his credibility on the line in the reconciliation process with President Mahmoud Abbas' Fatah, after 10 years of internal Palestinian divisions. By Dec. 1, the Palestinian Authority is supposed to take full control of civilian matters in the Gaza Strip. The path is steep, but there are encouraging signs. On Nov. 1, the Palestinian Authority has regained control over the border crossings with Egypt and Israel.

"I was surprised by the concessions Sinwar was willing to make," notes Ahmed Yousef, a moderate political figure inside Hamas. "Maybe he's understood how miserable life was and how much of a failure the national project was. He knows how to talk to people who suffer; and to young people, he speaks with his heart. Even his simple clothes work in his favor."

His belligerent tone sometimes sparks tensions inside the movement, especially among the most conservative senior activists. Before the Palestinian government's return to Gaza in early October, Sinwar had promised to "break the neck" of anybody who would disrupt the reconciliation process. "This wasn't diplomatic. He was criticized for it inside the movement," says Yousef. "You don't talk like that to your brothers. Everybody has made sacrifices."

Shaking things up with more than words

Yahya Sinwar is shaking up Hamas not only with his words but also, and most importantly, thanks to his ability to make decisions, meaning the decision process now takes place in Gaza only rather than abroad. Admittedly, the movement's transformation had been initiated before Sinwar's rise, because of growing isolation. For the past three years, the ceasefire with Israel has been respected, the ideological charter has been expurgated of its anti-Semitism. But Yahya Sinwar is, perhaps most importantly, the man behind the rapprochement with Cairo. The demands from the Egyptian president, Abdel Fattah el-Sisi, regarding the border with the Sinai have been met. This summer, a buffer zone was established to prevent the infiltration of ISIS jihadist fighters.

The new leader of Hamas has initiated the movement towards reconciliation out of calculation, not pacifism. Israeli sources reckon that 40% of the leadership comes from the military branch, whereas in the political bureau, one in every three members is a former prisoner. The management of daily business proved to be embarrassing over the past decade of misery under the blockade. On the other hand, they likely won't give up the fight. One of Sinwar's four brothers is a veteran from the al-Qassam Brigades, Hamas' military branch.

"Sinwar is open-minded, but he's a revolutionary," says Hamza Abou Shanab, an analyst close to Hamas. "He believes in the fight against Israeli occupation, even i it means sacrificing himself. Laying down the weapons would be submission."

Hamas, however, intends to work within the framework of the Palestine Liberation Organization (PLO). "We're entering a new era, that of Palestinian consensus," predicts Ghazi Hamad, who's in charge of foreign relations. "All factions will abide by the decision, whether it's war or peace."

Though Hamas isn't a monolithic organization, it is disciplined. One of the senior leaders, former health minister Basem Naim, insists that it's "not a one-man show." But he doesn't minimize Sinwar's role either. "As the number one, he's imposing his mark. When you've been in Israeli jails for so long, you have the experience of political processes. Mandela spent 27 years in jail and he became president!" The comparison between the late South African president and the leader of an organization classified as terrorist can only shock Israelis. The Netanyahu government demands that Hamas recognize Israel, free its hostages in Gaza and dissolves the military branch. Then, and only then, will he believe it's changed.

Everyone in Gaza remarks on Sinwar's charisma and authority. Even a former rival such as Hisham Abed Rabbo, who now lives in Khan Younis, in southern Gaza. Sinwar's former family home used to be just a few meters from his. He's 55, just like his former neighbor. A senior figure in the Marxist organization Popular Front for the Liberation of Palestine (PFLP), he remembers his former schoolmate well. At the time, he was already an activist inside the Mujama al-Islamiya, a pious organization founded by Sheikh Ahmed Yassin and precursor of Hamas.

Khan Younis refugee camp where Sinwar grew up — Photo Alberto Hugo Rojas

"His family was religious, conservative," Hisham Abed Rabbo says. "He and his brothers would go to the mosque, something that only old people used to do back in the days. At around 17, we started joining different factions and we became enemies. His group was targeting unveiled women and saw us as infidels." Then, the religious commitment gave way to "armed resistance" against Israel.

When Sheikh Yassin decided to create a paramilitary wing, named al-Majd, Yahya Sinwar became one of its pillars. Part of his mission consisted in tracking people whose morals were deemed deviant, but most importantly those who were collaborating with the Israelis. He would then interrogate them, and sometimes take the most extreme of measures. Accused of having killed several people, Sinwar was eventually arrested, as was Hisham Abed Rabbo. The two ended up in the Israeli prison of Ashkelon in the summer of 1989. Though the only member of the PFLP in the collective cell, Yahya Sinwar took Abed Rabbo under his wing, despite the blood spilled between their families. "I was alone, weak, and wounded after my interrogations. He took care of me and reassured me," Abed Rabbo remembers.

Prison sharpened his knowledge of the Israelis

Sinwar spent 22 years behind bars. His detention has sharpened his knowledge of the Israelis. He spent a lot of time reading, learned Hebrew, and established himself as a key intermediary inside the prison. Having received three life sentences for crimes committed in the West Bank, Mahmoud Mardaoui met Sinwar in Ashkelon in 1996. "He was a leader in all aspects of life. He used to cook for others, he read a lot. He was in liaison with the movement's foreign leadership. One day, someone managed to bring a cellphone inside the jail. He said, ‘This isn't for you to call your families, it's to help you to be sent home to them.""

With this phone, Sinwar intervened in the negotiations to liberate Gilad Shalit, an Israeli soldier detained by Hamas. More than 1,000 Palestinian prisoners, included Sinwar himself, were eventually freed in 2011, but he had opposed the first Israeli offers, which he deemed to be insufficient.

Since his release from jail, his rise has been spectacular. The Israelis think he will return to his roots as soon as the veil of reconciliation gets torn apart. Others claim he's a pawn in the hands of Egypt waiting for the post-Abbas era to come. "I told him more than once: ‘Be more diplomatic, be careful with the media,"" says Mardaoui with a smile. He and Sinwar see each other often. "He first says yes, but then he answered: ‘I am how I am." That's how he made himself heard by people who hadn't ever listened to Hamas before."