“When I look back at the chain of events I think we made a mistake,” one Israeli official who had worked in Gaza in the 1980s said in a 2009 interview with the Wall Street Journal’s Andrew Higgins. “But at the time nobody thought about the possible results.”

Higgins’s article is worth reading in full. He goes on to outline the type of assistance the Israelis initially gave Yassin, whom the PLO at one time deemed a “collaborator,” and Gaza’s other Islamists:

Israel’s military-led administration in Gaza looked favorably on the paraplegic cleric, who set up a wide network of schools, clinics, a library and kindergartens. Sheikh Yassin formed the Islamist group Mujama al-Islamiya, which was officially recognized by Israel as a charity and then, in 1979, as an association. Israel also endorsed the establishment of the Islamic University of Gaza, which it now regards as a hotbed of militancy. The university was one of the first targets hit by Israeli warplanes in the [2008-9 Operation Cast Lead].

Yassin’s Mujama would become Hamas, which, it can be argued, was Israel’s Taliban: an Islamist group whose antecedents had been laid down by the West in a battle against a leftist enemy. Israel jailed Yassin in 1984 on a 12-year sentence after the discovery of hidden arms caches, but he was released a year later. The Israelis must have been more worried about other enemies.

Eventually, the tables turned. After the 1993 Oslo accords, Israel’s formal recognition of the PLO and the start of what we now know as the peace process, Hamas was the Israelis’ bete noire. Hamas refused to accept Israel or renounce violence and became perhaps the leading institution of Palestinian resistance to Israeli occupation, which, far beyond religious ideology, is the main reason for its continued popularity among Palestinians.

Yassin was killed in an Israeli airstrike in 2004. In 2007, after a legitimate Hamas election victory that rankled both the West and Fatah, the Islamist group took over Gaza — a move that led to strict Israeli blockades and the grinding cycle of conflict that is once more repeating itself.

But, as Aaron David Miller, a Middle East expert at the Woodrow Wilson Center, observes, a strange, self-sustaining relationship remains. Israel’s hawkish government — comprising many politicians who have little interest in seeing the creation of a separate Palestinian state — dwells on the security threat that Hamas’s crude rockets pose. Hamas depends, Miller writes, on “an ideology and strategy steeped in confrontation and resistance.”

And so, he concludes, they are “two parties who can’t seem to live with one another — or apparently without one another either.”