U.S. withdrawal from Syria puts a check on mission creep

As dire as the situation in Syria may be, President Trump's decision to withdraw U.S. troops from Syria could well prove the lesser of two evils.

The big picture: The U.S. military presence in Syria has continued despite its lack of congressional authorization or coherent strategy, risking another long entanglement of U.S. forces in a Middle Eastern country. It is also illegal under international law.

Background: The Obama administration first deployed U.S. troops to Syria to complement its aerial bombing campaign against the Islamic State, or ISIS, with special operations forces and to coordinate with local anti-ISIS militias on the ground, gradually expanding from hundreds of troops to roughly 4,000.

• The mission expanded, too, from merely defeating ISIS (substantially accomplished some time ago) to ushering Syrian President Bashar al-Assad out of power, expelling Iranian forces and edging out Russia.

The other side: Trump’s decision has come without a clear public explanation or the kind of careful inter-agency process that would enable the most responsible withdrawal (though the fault for that may lie more with his hawkish advisers).

• Moreover, Syria is unlikely to achieve peace and security in the near term: The Turks may engage in operations against the Kurds in Syria’s northeast, and ISIS may make some gains.

Yes, but: That doesn’t justify an unauthorized and indefinite military presence.

• U.S. diplomats can try to curb Turkish plans against the Kurds.
• ISIS' permanent defeat probably does not require a U.S. ground presence in Syria. ISIS is already decimated, and it's surrounded by enemies determined to nip its potential re-emergence in the bud.
• It's impossible for the U.S. to forestall every unwanted contingency in the region. Just as ISIS itself was a byproduct of the U.S. invasion of Iraq, so too could a continued presence in Syria create unintended consequences.

The bottom line: Absent achievable goals and a strong national security imperative backed up by congressional authorization, the U.S. presence in Syria is illegitimate and better off wound down.

John Glaser is director of foreign policy studies at the Cato Institute.