President Obama’s less-than-penetrating observation last month that the protesters in Egypt wanted “change” is obviously correct. But despite the president’s affection for the word, there is very little assurance of what “change” will bring and whether it will be congruent with American principles and interests.

It is too soon to tell the nature of Egypt’s revolution and what form of government will ultimately emerge. The same is also true in Tunisia, Bahrain, Yemen and Libya. As the United States responds to these developments, it is useful to consider how America responded to revolutions in Latin America nearly two centuries ago.

As the peoples of Latin America were throwing off the yoke of Spanish imperial rule in the early 1800s, they appealed to the United States for support. James Madison described their efforts as part of “the great struggle of the Epoch between liberty and despotism.”

Despite the grand hopes for “our brethren to the South,” however, the situation on the ground gave pause to American statesmen. They realized that the people of the new republics had not only to throw off the Spanish Empire, but had to establish free and stable governments in keeping with the principles of liberty before Americans could truly celebrate their success. Prudence led the United States to wait nearly four years before officially recognizing their independence and engaging in treaties of commerce with the new republics.

During that time, however, Secretary of State John Quincy Adams and other American diplomats were working vigorously to see that the new republics’ independence was assured and that the principles of liberty prevailed in their new governments. Despite U.S. diplomatic support, it was clear that America’s material aid depended on the nature of their regime and also their respect for international treaties, including freedom of commerce. As long as America was convinced that the nations followed a republican path to self-government and behaved responsibly among the nations of the Earth, they had her moral and diplomatic support.

The U.S. did not avoid protecting its interests either. American diplomats demanded that the new nations prevent privateers from operating off their coasts, from which they harassed peaceful American ships of commerce and endangered American lives. With added diplomatic pressure, the government in Buenos Aires complied and put an end to privateering. The way was then clear for U.S. recognition.

In a special message to Congress on March 8, 1822, President James Monroe officially recognized the independence of Argentina, Peru, Chile, Colombia and Mexico. The United States was the first established nation to welcome these new republics into the community of nations.

Far from being isolated or diplomatically insignificant, these actions represented America’s leading role in supporting the cause of liberty abroad at that time. It also made clear that American support for a new government was conditional on both America’s political principles and national interests.

The United States should make it clear to the emerging Arab governments that American moral and material support is contingent on their adherence to the principles of freedom and on their commitment to preventing radical Islamic terrorism from flourishing in their territory. The United States should stand resolutely by its principles and for its interests but should not stand prematurely with any new factions in Tunisia, Egypt, Bahrain, Libya or Yemen.

At the same time, the U.S. should work to keep other foreign influences, such as al Qaeda or Iran, from intervening and poisoning these tender sprouts of liberty, just as American diplomacy did for the new Latin American republics by working with England to prevent Spain and France from retaking the new republics.

Years of this sort of principled, but prudent, diplomacy finally culminated in the Monroe Doctrine in 1823, when circumstances allowed for a more robust military policy in the region. In the Middle East, though, military interventions are extremely risky and expensive means of supporting new democracies, as the 2003 invasion of Iraq demonstrated.

Such revolutions offer the United States an opportunity to advance its principles through the conduct of foreign policy. Such an approach is neither isolationist nor interventionist — it is prudential and principled.

Alas, this is not what we’ve seen from the Obama administration. It contradicted itself on Hosni Mubarak’s removal in Egypt and appears dumbstruck at events unfolding in the Middle East. The administration’s conflicting, incoherent and timid statements have highlighted the absence of prudence in our modern statesmen and the lack of a grand strategy.

Only when guided by justice and exercising prudence can the United States safeguard its long-term interests. America has a window of opportunity in the Arab world: It can either resolutely voice the founding principles that have defined its success or remain a hesitant, pragmatic spectator of an epic scene in history. One thing seems quite obvious: Mr. Obama’s doctrine is no Monroe Doctrine.

Marion Smith is a graduate fellow in the B. Kenneth Simon Center for American Studies at the Heritage Foundation