We stood up for, in no particular order, the Greeks, the Flips, the Turks (all against international Communists in the 50's), the Germans, the Austrians, the Izzies, the Egyptians (against Russian subversion), the Ethiopians (until Jimmuh showed up), the Afghans (until Jimmuh showed up), the Brits, the Frogs, the Taiwanese/Kuomintang, the Salvadorans, the Dominicans, the Cubans (so it didn't work -- so sue me), the Viets, the Laotians, the Khmers, the Thais, the Panamanian democrats, the Venezuelans and Indonesians (against the Communists in the 60's), the Chileans (ditto in the 70's), and who else have we got?
It's not like we've been lying down, eating grapes.
Life was easier in a bipolar world when the Soviet Union and the US were the two superpowers. The threat of Communism helped unify us in ways that are difficult today. Perhaps, if we could get pass political correctness, we could identify radical Islamic fundamentalism as the enemy.
The US is bankrupt. We have spent blood and treasure protecting freedom and democracy. The future bodes a decline in our global presence and role because we can no longer afford the costs. Just as the British Empire declined gradually, e.g., no troops East of Suez, we will be faced with similar choices. And don't underestimate the impact that being the world's biggest debtor will have on our foreign policy. You can't afford to piss off the people who hold your debt--namely the PRC.