David Rockefeller, the former chairman and CEO of Chase Manhattan Bank, makes a compelling historical case in today’s New York Times for pursing free trade policies. Rockefeller has been around long enough to remember the Smoot-Hawley tariff bill of 1930 and the Great Depression that followed. In an op-ed piece titled, “Present at the Trade Wars,” he writes:

I lived through the stock market crash of 1929 and the Great Depression that followed it, and I saw that there was no direct cause and effect relationship. Rather, there were specific governmental actions and equally important failures to act, often driven by political expediency, that brought on the Depression and determined its severity and longevity.

One critical mistake was America’s retreat from international trade. This not only helped to turn the 1929 stock market decline into a depression, it also chipped away at trust between nations, paving the way for World War II.

On the eve of the G‑20 summit in Pittsburgh this week, Rockefeller offers a timely warning to President Obama not to repeat the mistakes of the past.