The United States government has formally announced that it’s going to arm Kurdish militias in Syria in a bid to capture the city of Raqqa from ISIS, the “capital” of the Islamic State’s “caliphate.”

It’s about time.

The YPG, or Kurdish Protection Units, is the largest faction in the Syrian Democratic Forces and the military arm of the leftist Democratic Union Party. It is loosely aligned with the PKK, or Kurdistan Worker’s Party, in Turkey, and has carved out an autonomous region in northern Syria which the Kurds call Rojava. It is, as the Pentagon put it, ““the only force on the ground that can successfully seize Raqqa in the near future.”

The Obama administration crafted the plan last year, and the Trump administration initially scrapped it, assuming, for reasons we can only guess at, that the White House could come up with a smarter plan. Arming the Kurds, though, has been the smart plan from day one of the Syrian conflict even though years passed before anyone in Washington figured that out. As Winston Churchill famously said, “You can always count on Americans to do the right thing – after they’ve tried everything else.”

Aside from the Israelis, the Kurds are the Middle East’s most capable fighters. The majority are Muslims (a minority are Yezidis and Christians), yet they are as allergic to radical Islam as Americans are. They are among the most staunchly pro-American people in the entire world and make perfect military allies.

If the United States wants indigenous ground forces in Syria to fight ISIS so that our own soldiers don’t have to go in there and do it, the Kurds are the only viable option. Contrary to popular belief, Bashar al-Assad’s Arab Socialist Baath Party regime is not fighting ISIS, nor are the Russians. Assad’s forces are fighting just about every armed group in the country except ISIS.

There are more active militias in Syria right now than just about anyone can keep track of, but most of them, alas, are Islamist, and the vast majority would rather fight Assad than ISIS. After six years of war, political moderates who haven’t already been killed have fled by the millions.

So why didn’t we arm the Kurds earlier? Actually, we did. We just didn’t want the world to know we were doing it.

Two years ago, Eli Lake published a quickly-forgotten Bloomberg View column about a U.S. weapons airdrop in Syria supposedly intended for the Syrian Arab Coalition. The problem is, the Syrian Arab Coalition isn’t real. It’s a made-up front group that exists solely on paper so the Obama administration could say it was arming Arabs when it was really arming Kurds. An unnamed U.S. official admitted to Lake that the group is a “ploy,” and Syrian Kurds confirmed that they received weapons and ammunition.

“With this new support,” YPG commander Sipan Hemo said at the time, “the cooperation we have had for a year has reached a new level. And we hope to increase our work together even more, we hope to work strategically.”

The Pentagon “grew weary of denying reports it was already arming the YPG,” former Obama administration official Fred Hof recently told Alex Ward at Vox in an interview. “The new announcement at least regularizes matters.”

There are two reasons the U.S. didn’t want anyone to know we were arming the Kurds. First, the Kurdish militia and the political party behind it are not only avowedly secular and feminist despite being mostly made up of Muslims but also quasi-Marxist, and the Arabs in northeastern Syria, far more than those in Damascus and Aleppo and along the Mediterranean coast, are staunchly conservative. If the YPG ends up taking Raqqa, there could well be political and cultural clashes as well as ethnic clashes. Everybody in Syria understands this, so it’s sensitive.

The biggest reason, though, is because arming the Kurds enrages the Turks. The Turkish state has been fighting a low-grade counterinsurgency with the Kurdish PKK in eastern Turkey since 1978, both the U.S. and Turkey list the PKK as a terrorist organization, and the YPG is Syria is linked to the PKK.

Roughly 50,000 people have been killed in the Turkish-Kurdish war during the last four decades, and if the PKK were to win, Turkey could lose a substantial portion of its territory in the east. Once the Syrian war got going in earnest and Kurdish militias carved out de-facto sovereign territory along the Turkish border, Turkey decided the Kurds were the greater of evils and threw its tacit support behind ISIS by bombing Kurdish positions while allowing ISIS to smuggle people and weapons over the border.

For years, we pretended Turkey wasn’t helping ISIS. And we pretended we weren’t arming the Kurds while the Turks pretended to believe us. That’s over now. And in response, Turkey is threatening to step up its attacks against Syria’s Kurds.

“Turkey reserves the right to take military action,” a Turkish official told The Washington Post.

Let’s be clear about something here. The Turks are already attacking American-backed forces in Syria. From their point of view, the United States is now a state sponsor of terrorism. The way everyone else sees it, though, Turkey is at war with America’s best and only real allies in Syria at a time when every other country on earth wants ISIS destroyed yesterday. Turkey’s continued membership in NATO has never been so tenuous.

Ankara has since reversed itself and no longer gives ISIS a pass, and that is excellent, but it’s not good enough. If the Turkish government insists on bombing the only army in Syria that can effectively take on ISIS and win, it will—again—be objectively pro-ISIS. It will also be killing American allies, arguably an act of war against the United States. Under no theory should Washington shelve the only realistic plan to beat ISIS because a hostile government says so.

Semi-independent nations like Iraqi Kurdistan and Rojava have a right to exist even if they’re inconvenient to Turkey, and the Turkish state will eventually have to make peace with them. Americans will be more than happy to help. It would be as easy as taking a nap compared with resolving the Arab-Israeli conflict, for sure. In the meantime, it is insanely not in our interests to prioritize a b-rate regional squabble with no end in sight over the destruction of a worldwide terrorist menace that massacres people from San Bernardino to Paris. If the Turks don’t like it, that’s their problem.

Michael J. Totten is a contributing editor of The Tower and the author of seven books, including Where the West Ends and Tower of the Sun.