American interests in Syria and the Turkish invasion

"Even when Trump has good instincts - such as his desire to 'get out of the nation-building business' and avoid an open-ended U.S. commitment in places such as Afghanistan or Syria - his impulsive approach to decision-making leads him to implement those instincts in the worst possible way, with neither adequate preparation or sufficient regard for the longer-term consequences." -Stephen Walt, Welcome to Trump's Impeachment Foreign Policy Foreign Policy

The fiasco currently unfolding with the Turkish invasion of Syria is a prime example of this. A long-term direct US military presence to protect a quasi-independent Kurdish state would not have been a desirable or practical thing. But given the role that the Kurdish local government and military forces played in fighting ISIS in conjunction with the United States, and given how Kurds there have been targeted by their enemies in Turkey and in Syria, the Kurdish areas should have probably been the last place from which to withdraw US troops from Syria.

A major complication in the situation is that Turkey is a NATO ally of the US. So the US does have to pay attention to (actually legitimate) security concerns of Turkey, including those related to armed attacks from Kurdish forces.

But NATO is a defensive alliance, not an alliance to support Turkey invading Syria. And certainly not an alliance to support Turkey carrying out an ethnic cleansing operation against the Kurds in Syria. NATO is supposed to defend legitimate borders, not encourage its members to violate them. (And, yes, that applies to the US-British-French intervention in Libya in 2011, approved by President Obama and Secretary of State Hillary, an action that is still producing destructive consequences.)

It's worth recalling that the NATO alliance does not automatically obligate a member nation to support a military action of one member state. And certainly not in an illegal war of aggression. In this case, the NATO countries including the US should be pressuring Turkey to withdraw from Syria.

Given that larger context, this piece by Paul Pillar provides an unsentimental look at US interests in Syria, Donald Trump's Syria Withdrawal: Are We Asking the Right Questions? The National Interest 10/09/2019:

The reported procedure through which Trump reached the decision is hard to defend. It appeared to be an impulsive act, reached after a phone call with Turkish President Recep Tayyip Erdogan, that was not vetted through the relevant policy bureaucracy and caught much of that bureaucracy by surprise. Such a broken method of presidential decision-making has produced bad policy in the past (not just in the current administration) and will continue to produce bad policy in the future as long as Trump uses it. But the procedure is not the same as the substance. Even a broken clock is right twice a day.

Or, in Rick Perry's famous formulation, it's right once a day. Which is a better analogy for the Trump Presidency.

Pillar goes on to describe some of the practical, power-politics realities:

[T]he Kurds did not do what they did on the battlefield as an act of generosity to the United States. Trump captured only a portion of what needs to be noted in this regard with his tweet saying that the Kurds were “paid massive amounts of money and equipment” for their fighting. The Kurds also had a direct interest in defeating ISIS, and they have been playing they own political-military game regarding their relationship with Syrian Arabs. [my emphasis]

He emphasizes this point, which surely weighs heavily in the NATO leaders' view of the situation:

A direct organizational connection links the Kurdish militia in the region in question, the People’s Protection Units (YPG), to the Turkish Kurdish resistance movement, the Kurdistan Workers’ Party (PKK), which has spilled much Turkish blood over more than three decades through international terrorism and insurgency in southeastern Turkey. Americans who are quick to condemn anyone with the slightest “link” to anti-U.S. terrorist groups would be just as hardline toward the Syrian Kurds if placed in Erdogan’s situation. [my emphasis]

The PKK wasn't the only group with "links" to terrorists. The US has also provided aid to some Sunni fundamentalist military groups opposed to the Alawite government of Syrian President Bashar al-Assad during the Syrian civil war.

Pillar also argues on the question of the larger US troop presence in Syria:

ISIS is not out even if it is down, but with the physical caliphate erased from the map, the remaining counterterrorist tasks are not primarily ones that troops on the ground can accomplish. They tend to be more ones in which a foreign military presence is more of a provocation than a help. Any possible resurrection of the caliphate would be at least as much a matter for the Syrian regime and other players in the immediate vicinity to tackle as it would be for the United States. [my emphasis]