Despite the president’s declaration last year that American troops would soon begin leaving Syria, about 1,000 remain. Charles Lister argues that their presence in the country serves vital U.S. interests:

What happens in Syria does not stay in Syria. We ought to have learned that lesson by now. The first three years of the Syrian conflict brought us Islamic State (IS), the most powerful and wealthy terrorist organization the world has ever seen, along with its now-global network of “provinces.” It also catalyzed a massive refugee flow that has crippled Syria’s neighbors and destabilized European politics, fueling populist and far-right movements. War crimes were, and continue to be, a daily affair, committed with total impunity. The global norm against the use of chemical weapons has been demonstrably eroded. In more recent years, Iran has expanded regionally like never before, and Russia has emerged as a genuine competitor to U.S. influence in the Middle East. Although Syria in 2019 may look different from Syria in 2014, none of these issues has been resolved; most are likely to sustain themselves into the future, and many may yet worsen.

While certainly not a solution [to these problems], our presence affords us more influence over Iran’s ambitions in eastern Syria than we’d have if we left, and it has a reassuring effect on our ally Israel, amid its more kinetic campaign against Iran and its proxies. More broadly, by remaining in Syria, . . . the United States is a more credible actor than it would be if it promptly left—an act that would destroy our influence in Syria for good.

IS now maintains thousands of sleeper cells across Syria and Iraq, which are collectively sustaining a “resurgent” insurgency, to use the term the Department of Defense employed in a deeply negative August 2019 assessment. . . . A premature departure from Syria now would inflame existing problems and guarantee future threats that the U.S. would have to confront, but without any future means of doing so.

As for the argument that Russia can be relied upon to defeat Islamic State, Lister notes that “for Moscow, combating opposition forces will always take precedence over fighting IS—as it has done every day since Russia intervened nearly four years ago.”

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.