One of Donald Trump’s most foolish foreign-policy proposals is to team up with Iran, Russia and Bashar al-Assad to defeat the Islamic State in Syria.

“I don’t like Assad at all, but Assad is killing ISIS,” the American president-elect said last month, referring to the self-proclaimed Islamic State by an acronym.

“Russia is killing ISIS and Iran is killing ISIS.”

If that were true, a pact might make sense. But it isn’t. And even if it were, the arguments are against an alliance.

Russia doesn’t care about the Islamic State

Russia has justified its intervention in the Syrian war by claiming it is fighting “terrorists” alongside Assad.

This has fooled gullible Westerners like Trump, but a quick look at a map of Russian airstrikes in Syria reveals something else: It is helping Assad gain back control over western Syria by bombing his less fanatical opponents.

From the start, Russian warplanes have carried out far more bombings in the vicinity of Assad’s Alawite homeland on the Mediterranean coast than in the eastern desert, where the Islamic State is headquartered.

Assad’s loyalist and Shia forces, including troops from Hezbollah and Iran, have similarly conducted the majority of their operations in the west of Syria, in and around the provinces of Aleppo, Hama and Homs.

They have seldom engaged the Islamic State’s fighters, who do battle with Iraqi and Kurdish soldiers across the border.

The greater threat

So Trump is wrong about that. But let’s imagine things change and Assad, Iran and Russia decide to join the war against the Islamic State once the Republican takes office next year. Would an alliance make sense then?

Only if you think the Islamic State is a greater threat to American interests than Iran, argues Adam Garfinkle, a Middle East expert, in The American Interest. And it isn’t.

Look at its order of battle — in its strongest stronghold of Mosul, ISIS fields fewer than 4,000 soldiers, with no air force or useful air defense. It just lost one of its provincial redoubts in Libya. It’s running out of money and recruits. It is by any measure pathetic. The LAPD could probably handle it and let the 82nd Airborne play golf instead down there near Fayetteville.

Alarmism about the Islamic State and terrorism in general is not unique to Trump. Many Republicans, as I reported here last year, believe the West is engaged in some kind of civilizational struggle with radical Islam. That hugely overstates the threat it poses.

Turks and Kurds

There is another factor here: Turkey. This is where Trump’s ignorance of American foreign policy becomes even more cringeworthy and the damage he could do reaches new heights.

America’s NATO alliance with Turkey hugely complicates the Syrian conflict.

Trump and Turkey’s president, Recep Tayyip Erdoğan, seem to like each other. That is what strongmen do, according to Garfinkle:

They think they can sit down together and clear away all the niceties and diplomatic persiflage, get down to the proverbial brass tacks, make a deal and get on with it.

But it never works that way. Turkey and the United States have contradicting interests in Syria. No personal accord between their leaders can paper over that.

Even though Turkey has been rocked by Islamic State attacks, it still considers Assad the greater threat.

With reason: It arguably was Assad who allowed the Islamic State to flourish by killing everybody else who opposed his dictatorship. From the beginning of the uprising in 2011, Assad has maintained that the choice is between him and madness — and he made sure madness prevailed on the other side.

Turkey’s hands aren’t clean either. It refused to close its southern border and allowed foreign fighters to cross into Syria to join the jihad there. Now those fighters have turned their guns on the Turks.

America has a stake in this back-and-forth between Syria and Turkey, but it doesn’t rise to the level of a threat to the homeland.

The Islamic State does. Not because, as Trump and Republicans would have it, the group is so powerful, but rather because it is inspiring — and possibly to some extent coordinating — lone-wolf and loosely-organized terrorist attacks in Europe and North America. That is a manageable problem, but it is a problem.

The West’s allies are the Iraqi government and the Kurds, who live in the same areas the Islamic State claims for its caliphate. But the Kurds are considered a threat by Erdoğan. Like Turkish leaders before him, his overriding concern is not losing a fifth of Turkey’s people to a Kurdish state.

Which is why Russia, like the Soviet Union before it, is supporting Kurdish nationalists. It wants to divert Turkey’s attention away from Assad.

Does anyone think Trump, despite his professed “love” for the Kurds, understands this? I may not even understand half the emotional, historical and strategic complexities involved and it’s my job to!

It’s tempting to think the enemy of one’s enemy is one’s friend, but the world is rarely that simple. It’s because Syria is so complex — not because America is “weak” or its leaders are “stupid” — that there hasn’t been a better strategy.