Can we at least agree that U.S. President Donald Trump’s decision to strike three chemical-weapons facilities owned and operated by Syrian President Bashar Assad—vassal of the Islamic Republic of Iran and Russia—was consistent with American values?

The gassing of civilians by dictators is—for most of us, anyway—both morally repugnant and unambiguously criminal. Those who condone such practices, along with those who merely tut-tut about them, help normalize them.

War will always be hell, but to make war a little less hellish, civilized people establish rules and enforce them. If you’re not certain that Trump did the right thing, imagine the counterfactual: that he had let this red line be transgressed with impunity once again.

A note to those who believe Trump should have hit harder: Had the president launched this attack without partners, he’d have been derided as a unilateralist. It was imperative that he persuade French President Emmanuel Macron and British Prime Minister Theresa May to participate. Would they have done so if the mission had been more aggressive? Doubtful.

Can we also agree that it was in America’s national interest to launch this attack? One important reason why: It’s insufficient for America’s adversaries to know it has enormous power. They need to be convinced that the United States is prepared to use that power when it deems it necessary—without permission from the U.N. Security Council where Russia and China, illiberal and authoritarian states, exercise a veto.

When America’s threat to use force is credible, its adversaries are less likely to test it. That means it will need to go kinetic less often, not more. But like weeding gardens and whacking moles, deterrence requires repetition. U.S. Ambassador to the United Nations Nikki Haley was right to warn that the United States is “locked and loaded,” and will strike again should Assad and his foreign patrons need additional instruction.

So based on both values and interest, a useful mission was accomplished. Now, I hope, Trump will move on to other more challenging missions. The president and his reassembled team of advisers need to determine the highest-priority national-security goals in Syria and the region, and the best strategy to achieve them.

That strategy should be consistent with the broader National Security Strategy that Trump issued late last year. Unlike former President Barack Obama, who thought that Iran’s theocrats could be cajoled and bribed to fulfill what he called their “international obligations,” and who asked them if they would be so kind as to demonstrate that their nuclear program is “entirely peaceful” (it wasn’t and isn’t), Trump’s NSS harbors no illusions about the regime in Tehran.

A “rogue regime” is what the document calls it—one that sponsors terrorism and “openly calls for our destruction.” This much should be obvious: Just as it was not in America’s interests to have a wide swath of the Middle East ruled by an Islamic State caliph bent on global jihad, so it is not in its interests to have a wide swath of the Middle East dominated by an Islamic republic ayatollah bent on global jihad.

It is to create such an empire that the Iranian Revolutionary Guard Corps and militias drawn from the Shia of other nations have been deployed to Syria.

American forces, along with their Arab and Kurdish partners, have liberated about 30 percent of what used to be Syrian territory from Islamic State. As a result, the United States now controls as much as 90 percent of Syria’s prewar oil production, worth billions a year. Can we not agree that abandoning those resources, in effect turning them over to Tehran, Moscow and the mass murderer in Damascus, would be an error?

Look, I understand that many of Trump’s supporters are not enthusiastic about the prospect of American troops remaining in Syria. Though they quarreled with Obama on most issues, they were not necessarily opposed to his policy of withdrawing from the turbulent Middle East.

But that policy has resulted in more than 500,000 killed and 11 million displaced so far. Other consequences include a refugee flood into Europe and increased peril for the pro-American nations of the Middle East—Saudi Arabia, Iraq, Jordan, the United Arab Emirates and Israel among them.

Nearly 40 years after Iran’s Islamic Revolution—and almost 17 years since the attacks of Sept. 11, 2001—we (all of us, really) should understand that jihadism represents as serious a threat today as communism did yesterday. America’s leaders did not always fight the Cold War wisely. But fighting the Cold War was necessary.

The prospect of yet another low-intensity, long-term conflict is not appealing. The alternative, however, is not peace. The alternative is a high-intensity conflict eventually or (always an option) the slow-motion surrender of America and the West. “Better red than dead” was the argument Cold War defeatists used to make.

To paraphrase a quote widely attributed to Edmund Burke (no neocon he), all that is necessary for the triumph of evil is for good nations to do nothing. The triumph of evil, I hope we can all agree, is not in America’s interest. Meanwhile, the number of good nations willing and able to project power beyond their borders is not increasing, and the barbarians are becoming bolder.

If America is to remain good—not to mention great again—it cannot retreat prematurely from battlefields, further empower the authoritarians who dominate the United Nations, and attempt to mollify totalitarians who vow to destroy it. That was Obama’s approach. Can we not agree (most of us, anyway) that Trump should take a different path?

Clifford D. May is president of the Foundation for Defense of Democracies and a columnist for “The ‎Washington Times.‎”