After the Cold War ended in 1991, the United States emerged as the sole superpower with global influence. It maintained this dominance through international organizations like NATO and the UN. The September 11, 2001 terrorist attacks had a major impact, leading the US to declare a "War on Terror" under President George W. Bush. Several presidents since Clinton have governed from this position of American global dominance. However, periodic economic crises like the 1973 Oil Crisis and the 2008 global financial crisis have continued to impact the capitalist world.