The U.S. military, along with its allies in Syria, are planning to form a 30,000-man force to patrol the northern Syrian border.  The force will be composed mostly of Kurdish YPG militia and will be augmented by other Syrian rebel groups.

The reason for the force, according to the U.S. military, is to prevent ISIS from reconstituting.  But Turkish president Recep Tayyip ErdoДџan doesn't see it that way.  He is calling it a "terror army" and is massing troops on the border with Syria to destroy it.

Reuters:

The Syrian government of President Bashar al-Assad responded on Monday by vowing to crush the new force and drive U.S. troops from the country.  Assad's ally Russia called the plans a plot to dismember Syria and place part of it under U.S. control.

But the strongest denunciation came from Erdo[Дџ]an, who has presided as relations between the United States and its biggest Muslim ally within NATO have stretched to the breaking point.

"A country we call an ally is insisting on forming a terror army on our borders," Erdo[Дџ]an said of the United States in a speech in Ankara.  "What can that terror army target but Turkey?"

"Our mission is to strangle it before it's even born."

Erdo[Дџ]an said Turkey had completed preparations for an operation in Kurdish-held territory in northern Syria.

While the U.S. may see the force as a means to prevent ISIS from regaining its strength, the Kurds view the formation of a border army quite differently.  The Kurds have carved out a section of Syria and want to use the new army to protect it.  The U.S. has given tacit approval for this, although with ErdoДџan breathing fire about the "terror army" of Kurds, we won't be able to do too much to prevent Turkey from having its way.

For much of the war, the United States and Turkey worked together, jointly supporting forces fighting against Assad's government.  But a U.S. decision to back Kurdish fighters in northern Syria in recent years has enraged Ankara.

Meanwhile, the Assad government, backed by Russia and Iran, has made great strides over the past two years in defeating a range of opponents, restoring control over nearly all of Syria's main cities.  It considers the continued U.S. presence a threat to its ambition to restore full control over the entire country.

On Sunday, the U.S.-led coalition said it was working with its militia allies, the mainly Kurdish-led Syrian Democratic Forces (SDF), to set up the new force to patrol the Turkish and Iraqi borders, as well as within Syria along the Euphrates River which separates SDF territory from that held by the government.

Turkey views the Kurdish forces supported by the United States as a national security threat.  It says the Syrian Kurdish PYD movement and the affiliated YPG militia, the backbone of the U.S.-backed SDF force in Syria, are allies of the PKK, a banned Kurdish group waging an insurgency in southern Turkey.

"This is what we have to say to all our allies: don't get in between us and terrorist organi[z]ations, or we will not be responsible for the unwanted consequences," Erdo[Дџ]an said.

"Either you take off your flags on those terrorist organi[z]ations, or we will have to hand those flags over to you[.]  Don't force us to bury in the ground those who are with terrorists," he said.

"Our operations will continue until not a single terrorist remains along our borders, let alone 30,000 of them."

ErdoДџan wants the U.S. to actively oppose the force, which isn't going to happen.  But neither can we protect the Kurds if ErdoДџan follows through with his threats. 

The last several administrations have been ambivalent about Kurdish independence.  Emotionally, we support the Kurdish desire for a homeland.  But practically speaking, we can do little to help the Kurds advance that cause.  This has led to deep disappointment on the part of the Kurds and has put us at odds with the governments of Iraq and Turkey, two allies in the war against ISIS. 

ErdoДџan is using the "terrorist" excuse to destroy an effective Kurdish fighting force.  It remains to be seen whether they can stand up to the modern NATO army fielded by Turkey.