President Trump’s precipitous removal of U.S. protection from the Syrian Kurds, writes Dore Gold, is a cautionary reminder of the most fundamental principle of the Jewish state’s national-security doctrine: “that Israel must be able to defend itself by itself and not accept external guarantees, even from the United States, in lieu of its own self-defense capabilities.” With this in mind, Gold revisits the controversy surrounding Benjamin Netanyahu’s statement last month that, if reelected, he would extend Israeli sovereignty to the Jordan Valley. Gold goes back in history several decades to explain why Jerusalem must maintain a military presence in this area:

Alone, [the kingdom of] Jordan did not constitute an existential threat to Israel. . . . Israel’s eastern challenge historically has come from other states that exploited Jordan as a platform from which to attack Israel. Thus, in 1948 and 1967, an Iraqi expeditionary force, made up of one third of Iraq’s ground order of battle, crossed Jordan to attack Israel. Today, there are still multiple sources of instability to Israel’s east. For example, Iran projects its military power across the region through fully equipped Shiite militias which it has used successfully to defeat conventional armies in Syria and Iraq.

What the Jordan Valley gave Israel was not strategic depth, but rather strategic height. . . . When taken together, the lowest parts of the Jordan Valley and [the nearby] mountain ridge form a virtual strategic wall with a net height of 4,500 feet. This steep barrier provided a daunting challenge to [an enemy’s] armored and mechanized units.

The importance of the Jordan Valley was first recognized, Gold writes, by the celebrated Israeli general Yigal Allon, who in 1967 was deputy prime minister:

Allon . . . explained that any territory from which Israel would withdraw in the West Bank would have to be demilitarized. The question he posed was how demilitarization would be ensured. There was an arid zone, which included the Judean Desert, to the east of where the bulk of the Palestinian population lived. Allon estimated that this security zone was about 700 square miles. . . . That line would safeguard the demilitarization regime that he had in mind.

Why such a line was absolutely essential was demonstrated in 2005, when Prime Minister Ariel Sharon implemented his unilateral disengagement from the Gaza Strip. . . . Critics of the plan . . . stressed that Israel should at least retain the border zone between the Gaza Strip and Egyptian Sinai, known in Israeli parlance as the Philadelphi Route. [But it did not retain that zone.] What clearly happened in the aftermath of the Israeli pullout was a massive increase in weapons smuggling by Hamas and other Palestinian terror organizations from Egypt into the Gaza Strip. This directly influenced the rate of rocket fire on Israel.

Two extraordinary events demonstrate something important about Israel’s most fervent adversaries. One was a speech given at something called The People’s Forum (funded generously by Goldman Sachs), which stated, “When the state of Israel is finally destroyed and erased from history, that will be the single most important blow we can give to destroying capitalism and imperialism.”

The suggestion that this tiny state is the linchpin of a global, centuries-old phenomenon like capitalism goes well beyond anything resembling rational criticism. Even if Israel were guilty of genocide, apartheid, and oppression—which of course it is not—it would not follow that its destruction would help end capitalism or imperialism.

The other was an anti-Israel protest that took place in front of New York City’s Memorial Sloan Kettering Cancer Center, deemed “complicit” in Israel’s evils. At organizers’ urging, participants shouted their slogans at kids in the cancer ward, who were watching from the windows. Given Hamas’s indifference toward the lives of Gazan children, such callousness toward non-Palestinian children from Hamas’s Western allies shouldn’t be surprising. The protest—like the abovementioned speech—deliberately conveyed the message that Israel is the ultimate evil and its destruction the ultimate good, cancer patients be damned.

The fact that Israel’s adversaries are almost comically perverse does not mean that they can be dismissed. If its allies fail to understand the obsessive and irrational hatred that it faces, they cannot effectively help it defend itself.