This practice started with the retaliation operations of Unit 101 in the 1950s, payback for Palestinian terrorist attacks. It continued during the brief occupation of Gaza in 1956, during what Israel calls the Sinai Campaign (aka the Suez Crisis), and it resumed again during the early days of occupation after 1967, when Ariel Sharon — then an army commander, later the prime minister — set up death squads in Gaza.

It’s no coincidence that the First Intifada broke out in Gaza in 1987. And it’s no coincidence that Israel has embarked on three savage military offensives there over the past decade, killing thousands of people, wounding tens of thousands, leaving hundreds of thousands homeless and sowing unbelievable ruin. This would not have been possible in the West Bank, if only because there are too many Jewish settlements there now, abutting Palestinian villages.

The test case was Operation Cast Lead. In just over three weeks in December 2008 and January 2009, according to the Jewish Virtual Library, Israel killed 1,434 Palestinians in Gaza, many unarmed — compared with 14 Israelis, most of them soldiers, killed by Palestinians. The ratio is gruesome: about 100 to 1.

The world was put to the test then. Had it taken substantial action against Israel, the country might not have dared be so brutal again. A United Nations investigation known as the Goldstone Report cast heavy blame on Israel (and some on Hamas). Still, Israel read past the lip service and understood that it would have to pay nothing, not even for acts suspected of being war crimes or crimes against humanity.

Just three years later, in November 2012, it embarked on Operation Pillar of Defense, which was relatively restrained. But two years after that came Operation Protective Edge — the most brutal of its assaults on Gaza, which killed more than 2,200 Palestinians.

The decade-long siege of Gaza is an unparalleled collective punishment. Israel’s methods, disproportionate under international law, are carefully planned and considered. At one point, the military justified restrictions on food imports into Gaza by calculating the number of calories a person there needed daily to survive.