The reason is simple: Political and social systems that reward human creativity create wealth and lead to progress. Such progress is not fated by historical forces. Democracy is not inevitable like communism was said to be; it is inevitable like hope.

Second, the advance of freedom in the Middle East is America's best hope. Regimes that oppress their people are more likely to threaten their neighbors, support terrorist groups, feed anti-Americanism and anti-Semitism to distract from their failures, and seek weapons of mass destruction. Other democracies do not always do what we wish. But nations based on the consent of the governed are simply more peaceful than nations ruled by the whims of despots.

Of course there are challenges in promoting democracy -- how to best strengthen civil society, how to encourage not only elections but also constitutionalism, how to sequence reforms.

But the goal of democracy promotion is a consistent American commitment. It is the foreign policy consensus that emerged from World War II -- the bipartisan belief that America benefits from the expansion of free societies, free economies and a liberal trading order. And this belief led American presidents to proclaim the goal of universal freedom, even while occasionally dealing with dictators. Franklin Roosevelt sat with Stalin while defining four freedoms that apply "everywhere in the world." Ronald Reagan dealt with a Soviet leader even as he foresaw and hastened the downfall of the Soviet empire. Their democratic idealism did not prevent them from dealing with the devil; only from believing that the devils own the future.

Democracy promotion is difficult and reversible. It is also not new -- or optional.