As a model he pointed to American support for Joseph Stalin’s Soviet Union against Adolf Hitler’s Nazi Germany during World War II. With two totalitarian powers seeking to gain control of Eurasia, Washington believed it had to choose the lesser of two evils, which was the USSR at the time. After that conflict ended, the U.S. decided it had to contain Moscow.

Pipes also reminded readers that in 1987 he called on the West to back Saddam Hussein’s Iraq, which had been on the defensive since 1982 after starting the war two years before. However, “Looking to the future, should Iraq once again take the offensive, an unlikely but not impossible change, the United States should switch again and consider giving assistance to Iran.”

His policy of “propping up the side in retreat” has a certain cold‐​blooded Realpolitik core. But Pipes greatly overestimates Washington’s ability to manipulate international events. American policymakers lack sufficient knowledge of international conflicts and players and sufficient ability to make use of the knowledge that they have to effectively implement such a strategy.

Imagine Washington policymakers trying to carefully calibrate support for Assad so that it is sufficient to prevent his defeat, but not enough to enable his victory. Then to perfectly time a switch in allegiance from government to opposition to maintain the power equilibrium if Assad gained strength. And next to decide when both parties are sufficiently balanced to find new combatants to support. It beggars the mind.

Even if that was possible, how should Washington adjust to unexpected events? Former international prosecutor Carla Del Ponte announced in early May that there were “strong, concrete suspicions but not yet incontrovertible proof” that the Syrian opposition used Sarin gas. How should that change the interventionist equation? Perhaps Washington should bomb both sides simultaneously!

U.S. policy in World War II “worked,” to the extent that backing the Soviet Union can be called a success, because it made no pretense of nuance. Washington and the other allies chose to ally with Moscow and supported the latter all the way. There were a few advocates of the Pipes strategy — for instance, General George Patton suggested arming former Nazi soldiers and attacking the USSR. But most Americans believed that one big world war mid‐​century was enough.

Moreover, no interventionist policy could avoid the inevitable unintended consequences. A chief example is America’s policy in the Persian Gulf, much of which is an outgrowth of actions taken with almost frivolous disregard for consequences six decades ago.

In 1953 Washington fomented a coup against leftist Iranian Prime Minister Mohammed Mossedegh. His replacement, the Shah, was a reliable American ally, but an equally reliable thug. By brutally suppressing more moderate political elements and forcibly modernizing a traditional society he helped trigger the Islamic revolution, which in 1979 brought the Ayatollah Khomeini to power.

Fear of Iranian subversion and aggression in the Gulf led the Reagan administration to back Saddam Hussein after he attacked Iran. Then, believing that he had U.S. support or at least acquiescence, he attempted to swallow neighboring Kuwait. But Washington then intervened against him. However, the U.S. left him in power since it feared creating a power vacuum to be filled by Iran. At the same time, Washington kept troops in Saudi Arabia, which created one of the grievances that impelled Osama bin Laden to strike America on 9/11.

Subsequently the Bush administration invaded Iraq to “drain the swamp,” creating the previously feared vacuum which strengthened Tehran’s geopolitical position. If Washington ultimately ends up attacking Iran, the impact could be as extraordinary as it would be unpredictable. Unfortunately, the unintended consequences of the 1953 coup aren’t over yet.

Social engineering is hard enough — in fact, well nigh impossible — at home. It is even more difficult overseas. There is no easy way to transcend history, tradition, religion, ethnicity, geography, and much more. That’s the obvious reason why intervention so often fails, yielding counterproductive effects never imagined by its supporters.

Syria is among the more difficult cases facing the U.S. Half‐​steps, such as a no‐​fly zone, would entangle America without yielding a decisive result. Seizing Syria’s chemical weapons stores would ensure their use — against allied troops — and require lots of “boots on the ground.” An even larger occupation force would be required to defeat the regime, restore order, and enforce peace. With a war‐​weary public and bankrupt government, such a policy would be madness.

This is a time for leadership. To resist the rising pressure to intervene in Syria and other unnecessary conflicts. The fact that an argument can be made for backing most everyone in Syria’s tragic civil war may be the best evidence available that the only sensible course is to stay out.