Two weeks of zig-zag foreign policy by President Barack Obama — marching to war one moment, clinging desperately to diplomacy the next — culminated Tuesday night, appropriately enough, in a zig-zag address to the nation that did little to clarify what will come next in the Syria crisis but shined a glaring hot light on the debate in the president’s own mind.

The speech began with an earnest statement on behalf of Zig, a sober appreciation that military power has its limits and good intentions don’t necessarily equate to good policy: “I have resisted calls for military action because we cannot resolve someone else’s civil war through force, particularly after a decade of war in Iraq and Afghanistan.”

But it was followed the next paragraph by some piercingly indignant words making the case for Zag, the conviction that conscience and the obligations of global leadership sometimes require America to act.