President Donald Trump's administration inherited the Syria mess when it entered the White House on Jan. 20, 2017. Its policy was anyone's guess, reminding me of an old joke about an Irish farmer telling a tourist who asked for directions to Dublin, "Well, I wouldn't be going there from here." It is unclear how far Trump and his new foreign policy team, national security adviser John Bolton and Secretary of State Mike Pompeo, will commit the country's money, armed forces and intelligence services to Syria. They could, if they dared, learn from the mistakes of Obama's policies to avoid prolonging the war and deepening the United States' involvement in it....