If you're still unsure about whether President Trump did the right thing when he launched 59 cruise missiles at Syria's Shayrat air base last week, consider the alternative.
He knew that Syrian dictator Bashar Assad had yet again used chemical weapons to murder Syrian civilians, women and children prominent among them. He knew that Iran and Russia had enabled this atrocity, as they have many others. He knew he had two choices.
He could shrug, instruct his U.N. ambassador to deliver a tearful speech calling on the "international community" to do something, and then go play a round of golf. Or he could demonstrate that the United States still has the power and the grit to stand up to tyrants and terrorists — thereby beginning to re-establish America's deterrent capability.
In other words, this was what Sun Tzu and Carl von Clausewitz would call a no-brainer. (Well, loosely translated.) A mission was accomplished. Do harder missions lie ahead? Yes, of course. But I suspect Secretary of Defense James Mattis and National Security Adviser H.R. McMaster have made that abundantly clear to the new president.
We now know for certain that Russia failed to live up to its 2013 commitment to ensure that Mr. Assad surrendered all his illegal chemical weapons under the deal it brokered. Secretary of State Rex Tillerson acerbically questioned whether that was the result of complicity or incompetence, or whether Russia allowed itself to be duped by Mr. Assad.
The strike ordered by Mr. Trump was not "unbelievably small" — then-Secretary of State John Kerry's description of the punishment President Obama decided not to impose in response to Mr. Assad's earlier use of chemical weapons. It was big enough to make clear that American diplomats are again carrying big sticks. (For Mr. Obama to insist that diplomacy and force are alternatives was patently absurd.)
Conveniently, President Trump was dining with Chinese President Xi Jinping when the strikes took place. It's fair to speculate that Mr. Xi is today thinking harder about American requests to rein in Kim Jong-un, the North Korean dictator whose drive to acquire nuclear-tipped missiles that can reach the American mainland has become what Mr. Tillerson called an "imminent" threat.
Having passed his first major national security test, Mr. Trump is now obliged to demonstrate firmness and consistency. What plans might the Pentagon have on the shelf to respond to further provocations? The next round of Tomahawk missiles could permanently ground Mr. Assad's air force. That would make it easier to then establish no-fly zones. If such measures do not alter the calculations of Mr. Assad and his Iranian and Russian patrons, consideration could be given to leveling his defense, intelligence and command-and-control centers as well.
Another idea under discussion: setting up safe havens or, to use a better term, "self-protection zones" for those fleeing the Syrian regime and various jihadi forces, Sunni and Shia alike. Israel and Jordan could help the inhabitants of such areas adjacent to their borders defend themselves. The Saudis, Emiratis and Bahrainis could contribute to the cost. Might this lead to the partition of Syria? It's difficult to imagine a "political solution" that would not include such readjustments.
All this, while useful and perhaps even necessary, should be seen as insufficient. Syria is a major humanitarian catastrophe but only one piece in a much larger geopolitical puzzle. Sooner rather than later, the Trump administration needs to develop what Mr. Obama refused to contemplate: a comprehensive and coherent strategy to counter the belligerent, imperialist and supremacist forces that have emerged from the Middle East and are now spreading like kudzu around the world.
The Islamic State will, of course, need to be driven off the lands on which it has attempted to establish a caliphate. After that, its terrorists will have to be hunted, along with those of al Qaeda, wherever they hide (e.g., Egypt where, over the weekend, they bombed two Coptic Christian churches).
But — and this is crucial — accomplishing these missions must not serve to further empower Iran's jihadi rulers, who dream of establishing an expanding imamate, the Shia version of a caliphate.
Most immediately, Congress should send to Mr. Trump the legislation it is now considering to impose new sanctions on Iran in reprisal for its continuing support of terrorists, its missile tests and its maintenance of more than 35,000 troops in Syria, including its own, those of its Lebanese proxy, Hezbollah, and Shia fighters recruited from Iraq and Afghanistan. Suspending Iran's deal with Boeing/Airbus would be useful, too. Only the willfully credulous believe that Iran's theocrats won't use such aircraft for illicit military purposes.
That the United States cannot solve all the world's problems was one of Mr. Trump's campaign themes. But the implication is not necessarily, as some of his supporters hoped, that he would turn a blind eye to all atrocities and threats not already within America's borders.
In the last century, most Americans recognized, in some cases with enormous reluctance, that there was no good alternative to doing whatever was necessary to rout the Nazis and communists, enemies whose goal was to kill off the democratic experiment.
In this century, jihadists and Islamists harbor the same ambition. We can attempt to appease them. We can try to make ourselves inoffensive to them. We can keep our hand extended, hoping that in time they will unclench their fists. Or we can decide instead to plan for a long war that will end with the defeat of these latest enemies of America and the rest of the civilized world. If Mr. Trump has grasped that within his first 100 days, he's not off to such a bad start.