The Act permitted initially up to 2,500 non-resident aliens (later expanded to allow up to 12,500) to enlist.
[1] The Act was pushed through Congress by Massachusetts Senator Henry Cabot Lodge Jr. during the Cold War, looking especially for recruits from the Eastern Bloc to form infiltration units working in that part of the world.
No German nationals or citizens of countries of the Marshall Plan or of NATO were eligible.
[3] For comparison, note that during World War II, foreigners who served just three years were entitled to citizenship.
World War II general and future U.S. president Dwight Eisenhower is quoted in a 1951 Time article as saying, "When Rome went out and hired mercenary soldiers, Rome fell.