Woodrow Wilson. Had we not given aid to Britain during WWI, we wouldn't have gotten involved militarily. Even if Germany lost in the end, the peace terms would be far less harsh. Hitler never rises to power, which means no World War II, no American interventionism, no Cold War. Which means no U.S. support for Israel, and no Operation Ajax, which means no anti-U.S. sentiment in the Middle East, which means nobody willing to fly a plane into one of our buildings.
Reductionism doesn't prove that you're intelligent. Rather, it outs you as an idiot.