President Trump’s decision to cancel his Latin America trip is lamentable but necessary. He is sending Vice President Mike Pence instead because the crisis in Syria demands the president’s full attention.

Over the weekend, the military forces of Syrian dictator Bashar Assad launched another chemical bombing attack in Douma, Syria, near Damascus. With the survival of his regime on the line, this tyrant has repeatedly resorted to using chemical weapons that are illegal under international agreements and which in 2013 he agreed not to use, make, or stockpile.