Was the Attack in Syria in the U.S. National Interest?

In a narrow sense, no.  The use of chemical weapons by the Assad regime poses no threat to America.

Yet, more broadly, the U.S. response was essential.

First, President Trump’s reference to “red lines” put America’s credibility on the line again.  President Obama’s empty threat of 2013 had degraded it with untold deleterious effects on our national interests.  (It undoubtedly disheartened our friends and encouraged our foes.  American indeed appeared as a toothless tiger.)  A repeat was an anathema. 

Second, America’s moral leadership is worth upholding.   We backed a century-old proscription against chemical weapons that earned respect for our role in the world of enforcing standards.  To the extent respect  translates into support for the U.S., that’s good for America.