[Jordan Michael Smith is a writer in Washington, D.C.]

On Dec. 20, 1989, nearly 30,000 U.S. troops invaded Panama and captured the country's military dictator, Gen. Manuel Noriega. The invasion lasted just over a month, and the U.S. military suffered just 23 casualties. Thomas Pickering was the U.S. ambassador to the United Nations during the conflict, and a key advisor to President George H.W. Bush as the United States solidified its position in Central America and ushered in a new age of interventionism in the post-Cold War era. For Pickering, however, the conflict now has a different legacy: He believes that the invasion of Panama helped lead America into the Iraq war.

The brief and relatively bloodless war in Panama convinced Americans that the use of force could easily solve their problems overseas -- and, what's more, that the United States could largely accomplish this on its own. The United States did not seek international approval before invading Panama, as it did before the first Gulf War. In a recent interview with Foreign Policy, Pickering noted that before the 1990 invasion of Iraq, "[W]e undertook quite a remarkable series of activities inside the Security Council," including resolutions that imposed economic sanctions on the country and, after the war, the establishment of a peacekeeping force to protect the Kurds.

Multilateralism came with costs, however. In their joint memoir, A World Transformed, Bush and his national security advisor, Brent Scowcroft, specifically cited the limits of the U.N. mandate to liberate Kuwait as a primary reason they didn't topple Saddam Hussein in 1990. But Panama showed what could be done when the United States acted alone. Fewer allies meant fewer restrictions. This was a lesson too well-learned -- as the 2003 invasion of Iraq proved.

Panama had a far deeper imprint on U.S. policymakers than on the public. "Having used force in Panama, and in Grenada in 1983, there was a propensity in Washington to think that force could provide a result more rapidly, more effectively, more surgically than diplomacy," Pickering said.

Indeed, from the perspective of the United States, the Panama invasion seemed to offer tantalizing results. "U.S. interests were advanced and protected," Pickering argued. The invasion succeeded in securing the Panama Canal, which was subsequently returned to Panama in 2000. "The canal's operation -- which is our primary strategic interest in Panama -- is still ongoing, and now the Panamanians are enlarging the canal," he said. The invasion also removed a brutal dictator, albeit one the United States had supported for many years, Pickering says -- another parallel with the regime of Saddam Hussein. And it "allowed for a change in government that was rocky, but not totally completely feckless or failing," demonstrating the benefits of U.S. power...