After the United States' involvement in World War Two it went from being the world's seventeen largest military to the first, its GDP doubled and it became the world's largest creditor. Additionally, it initiated the atomic age and formed the United Nations. After World War Two the US was so involved in the world's affairs and on the road to globalization that there really was no turning back. FWIW, I bought a shirt, I also donated $5k to the United Way last year. Charity may start at home, but that certainly doesn't mean it has to end there.