The stunning events in Syria, where one of history’s most brutal strongmen has just been forced to flee, remind us that even longstanding dictatorships can be hollow shells, with little to keep them intact when opposition mounts from within. 

Thus, U.S. policymakers should prepare now for the real possibility that, across the Middle East and elsewhere, the angry populations of other authoritarian nations could find inspiration from the toppling of Bashar al-Assad and mount new challenges to the brutal regimes that terrorize them.

Otherwise, Washington could find itself in the same place it has been all too often in the past—ill-positioned to capitalize on the opportunities that such stirrings around the world offer U.S. interests.

“Prediction is very difficult,” Niels Bohr, the Nobel laureate in physics, once said, “especially if it’s about the future!” Nowhere is such a note of caution more appropriate than in the effort to foresee global change. What will prompt a popular uprising (or, as in Syria, enable a rebel force to free a suffering people)? Nobody knows.

Nobody, for instance, could have predicted that a disgruntled fruit peddler would set himself on fire in the city of Sidi Bouzid in late 2010, igniting massive protests across Tunisia that forced strongman Zine Ben Ali to flee and launched the Arab Spring. Nor did anyone foresee that the Romanian people would find the courage to boo iron-fisted Nicolai Ceausescu off a stage and then capture, try, and execute him in late 1989.

History shows, however, that as with the toppling of communist governments in Eastern Europe in 1989, democratic progress tends to come in bunches of nations at once (as, too, does the retreat of democracy).

In his landmark 1991 book, The Third Wave, Samuel P. Huntington documented three waves of global democratization—the first for about a century starting in 1828; the second from 1943 to 1962; and the third from 1974 to 1990 (with two “reverse waves” of democratic retreat in between).

In essence, both democratization and anti-democratization are contagious, with each influencing the direction of other nations after implanting itself somewhere. And that’s likely truer than ever now because, in an age of mass communication, both democracy-seeking populations and would-be autocrats learn from what they witness elsewhere.

Why do mighty dictators fall? Often, it’s because they’re not as mighty as they think or as their cowed populace assumes.

Like Assad, Ben Ali and Ceausescu fell with astonishing speed once their populations found the wherewithal to challenge them—as if their dictatorships were houses of cards awaiting a strong wind. Libya’s Muammar Gaddafi and Egypt’s Hosni Mubarak also fell quickly during the Arab Spring, as did Ferdinand Marcos of the Philippines after a fraudulent election in 1986.

Could the future hold something similar for Iran’s Ali Khamenei and Russia’s Vladimir Putin—both of whom have faced sizable protests in recent years—or even China’s Xi Jinping and North Korea’s Kim Jong-un? In light of what nobody foresaw in Syria, we should at least entertain the possibility.

What we, as a nation, do today can come back to haunt us tomorrow. That’s because the populations of once-oppressed countries and their new leaders tend to remember where the United States stood at moments when those countries were charting a new path.

Ho Chi Minh sought U.S. support for an independent Vietnam after World War II, publicly quoting the words of our Declaration of Independence. Still, U.S. support for French colonial control prompted Ho to seek friends in Moscow and China instead, laying the groundwork for America’s disastrous war in Southeast Asia.

In 1953, Washington played at least some part in ousting the democratically-elected premier of Iran, Mohammad Mosaddegh, earning the wrath of many Iranians ever since. Then, in 2009, President Obama disappointed democratic activists by refusing to offer them U.S. support after a fraudulent Iranian presidential election.

Assad’s downfall could offer new opportunities for the United States by energizing democratic activists in the region and beyond. So what should Washington do?

It should put the nation more squarely on the side of those seeking to write their own future. It should, for instance, abandon the rose-colored hopes of presidents of both parties to seek a rapprochement with Tehran and instead build stronger ties with the Iranian people. It also should continue to strongly support Ukraine’s efforts to rebuff Russia’s attempted conquest, which would strengthen Putin’s autocracy at home by eliminating the example set by a nearby democracy.

“The day will come,” Russian activist Alexei Navalny wrote in Patriot, his posthumous memoir, “when speaking the truth and advocating for justice will be commonplace and not at all dangerous in Russia.”

Whether that day comes sooner or later, in Russia or elsewhere, Washington should be well-positioned to capitalize on it—not left flat-footed because it did not anticipate how quickly the world could change.

Lawrence J. Haas is a senior fellow at the American Foreign Policy Council and the author of, most recently, The Kennedys in the World: How Jack, Bobby, and Ted Remade America’s Empire.

Image: Mohammad Bash / Shutterstock.com.