On December 19, 2018, President Trump declared correctly that “we have won against ISIS,” and announced that the remaining 2,000 American troops in Syria would be withdrawn.

The president has made the right decision. Having won the war against ISIS, he does not want to lose the peace by getting into a military conflict with the Syrian dictator Bashar al-Assad’s forces, or with the Iranians or the Russians, or even with the Turks for that matter.

As the father of an Army officer who is in theater right now, I think I have a right to an opinion. And in my opinion, the desert sands of Syria are not worth a single American life.

Everyone agrees that the commander in chief should bring our troops home from any overseas combat theater as soon as the mission is complete.

But what is the mission?

Was it the defeat of ISIS? Or is it “regime change” and “nation-building”?

When President Trump took office, he was assured that the reason we sent troops into Syria in 2014 was to assist local Kurdish forces in destroying the Islamic State. He approved the continuation of this limited mission. This mission is now complete. The Islamic State no longer exists as a territorial entity.

To be sure, scattered bands of ISIS terrorists — numbering perhaps 500 — still operate in parts of eastern Syria. But the mopping-up operation can be done by the Turks, or by the Syrian army, or even by the Russians. It certainly does not require a continued US presence, and Trump has declared “mission accomplished.”

The Washington foreign-policy swamp is outraged by Trump’s “mission accomplished,” calling it “precipitous” and “reckless.”

What they are not telling you is that, for them, the “mission” was never primarily about ISIS; it was about eliminating the Assad regime. The Islamic State was simply a convenient cover to deploy troops into Syria. And now, having taken control of everything east of the Euphrates River with the help of the indigenous Kurdish population, they want to attack Assad.

Overthrowing the Syrian dictator has been their goal since the beginning of that country’s civil war in 2011. Two different aid programs, one run by the Pentagon and the other run by the CIA, were set up to fund and empower the Syrian rebels. Both failed to dislodge the Assad regime, and both were ended by Trump by mid-2017.

Still, establishment types managed to convince the new president to expand the scope of the Syria operation. In mid-January of this year, then-Secretary of State Rex Tillerson announced that the US intended to maintain an open-ended military presence in Syria to not only defeat ISIS but to oust Assad and counter Iran’s influence.

Even as late as this September, the Washington Post, citing unnamed officials in the State Department, claimed that Trump had agreed to implement a new strategy that indefinitely extended the military effort with the goal of “establishing a stable, non-threatening government acceptable to all Syrians and the international community.”

The same foreign-policy geniuses that gave us the endless wars in Iraq and Afghanistan were back, offering the same old tired, unworkable ideas: regime change and nation building.

This mission creep was sold to the president as a continuation of the war on ISIS.

But when he learned that the Islamic caliphate was no more, he rightly decided it was time for America’s boys and girls to come home.

The Syrian Civil War is over. Obama failed to give the Democratic forces there the support that they needed at a time when it would have made a difference.

If we stay in Syria very much longer we will wind up fighting not ISIS, but the Syrian government forces, and perhaps the Russians as well.

If we stay in Syria very much longer we will wind up fighting not ISIS, but the Syrian government forces, and perhaps the Russians as well.

Our forces east of the Euphrates have already destroyed a Russian armored column that was advancing on them in a hostile manner. That battle, which resulted in a couple hundred Russian casualties, could easily have escalated into a wider conflict.

Of course, Vladimir Putin is happy to see us pull out of Syria, but so what? Let Russia pour the blood of its young men into the desert sands of the Middle East for a change.

President Trump is criticized for making the decision to withdraw after consulting with President Recep Tayyip Erdogan of Turkey. But why shouldn’t we be working with our NATO ally, which has its own concerns about terrorists on its southern border?

The same people who love to attack this president for not working more closely with our NATO allies have now turned on a dime and are criticizing him for coordinating with Turkey. It’s a wonder that they don’t get whiplash.

Much of the angst in the Pentagon over America’s withdrawal from Syria has to do with the perception that we are abandoning our Kurdish “allies.” But the Kurds fought alongside us not because they had any particular affection for America, but because the caliphate was occupying their towns and villages.

I can understand the loyalty that some American commanders on the ground, including outgoing Defense Secretary Jim Mattis, feel for their Kurdish battle brothers. But I am glad that our president understands he was elected to keep Americans safe, not Kurds. And not Syrians, or Iraqis, or Afghans either, for that matter.

There is no reason to keep American forces in Syria.

In fact, there is no reason to keep American forces in harm’s way, separated from their families and loved ones, in any foreign country unless it directly benefits the United States in direct, tangible ways.

As for me and my family, we are looking forward to having our son home soon.

Steven W. Mosher is the president of the Population Research Institute and the author of “Bully of Asia: Why China’s Dream is the New Threat to World Order”