What other possible benefits are there from intervening? Washington has no prospect of stabilizing, let alone unifying, Syria. Helping oust Assad would aid, not deter, the rise of radical jihadists in Syria. Russia may favor Assad, but Moscow gets little benefit from his survival. In contrast, the United States already is allied with the most important Middle Eastern states, including Israel, Saudi Arabia, Egypt and Iraq.

Joining the Syrian killfest would achieve few humanitarian ends; to the contrary, the fall of Assad would only conclude the first round, leading to a struggle for supremacy among conflicting groups as well as revenge killing. Almost irrespective of the result, Washington would acquire new enemies.

And strikes tied to Syria’s alleged use of chemical weapons would be only the start. Advocates of full-scale war, such as Sen. John McCain, would continue lobbying for more. Even small-scale intervention would further invest the United States in the conflict, making it more difficult to avoid deeper involvement.

The United States should not get involved in Syria’s tragic civil war. Ronald Reagan inserted American forces in the middle of the Lebanese conflict and was forced into a humiliating retreat. Washington’s Iraq invasion triggered even worse bloodletting. Violent discord continues in Libya, another product of American intervention.

War is not just another policy option. Unintended consequences are constant and deadly. Washington’s chief responsibility is to defend America—its people, territory, constitutional system, liberties and prosperity. The government should not risk its people’s lives and waste their wealth for other ends.

The president won the Nobel Peace Prize, only to spend his first term fighting old and starting new wars. Congress should help him live up to his award by saying no to joining the war in Syria.

Doug Bandow is a senior fellow at the Cato Institute. He is a former special assistant to President Ronald Reagan and the author of several books, including Foreign Follies: America’s New Global Empire.