Conventional wisdom has it that Americans don’t care about foreign policy because they’re tired after more than a decade of conflict. But they’re certainly paying attention.

All it takes is the right combination of events to make it a winning campaign issue. This year it’s voter dissatisfaction with President Obama’s approach, highlighted by his weak response to the crisis in Ukraine, combined with the growing realization that the president’s spending plan for the Pentagon would leave the U.S. dangerously unprepared to meet challenges from foreign powers that can’t be resolved by diplomacy alone.