From the website: "U.S. policy allows refugees of special humanitarian concern entrance into our country, reflecting our core values and our tradition of being a safe haven for the oppressed.
The U.S. Congress enacted the first refugee legislation in 1948 following the admission of more than 250,000 displaced Europeans. This legislation provided for the admission of an additional 400,000 displaced Europeans. Later laws provided for admission of persons fleeing Communist regimes, largely from Hungary, Poland, Yugoslavia, Korea and China, and in the 1960s Cubans fleeing Fidel Castro arrived en masse. Most of these waves of refugees were assisted by private ethnic and religious organizations in the U.S., which formed the base for the public-private roles in U.S. resettlement efforts today.
With the fall of Vietnam in April of 1975, the U.S. faced the challenge of resettling hundreds of thousands of Indochinese using a Refugee Task Force and temporary funding. As a result, Congress realized the need for refugee resettlement services and passed The Refugee Act of 1980, standardizing resettlement services for all refugees admitted to the United States. This Act incorporates the definition of "refugee" used in the U.N. Protocol, providing for regular and emergency admission of refugees and authorizing federal assistance for the resettlement of refugees. The Refugee Act provides the legal basis for The Office of Refugee Resettlement.
Since 1975, the U.S. has resettled more than 3 million refugees, with nearly 77 percent being either Indochinese or citizens of the former Soviet Union. Since the enactment of the Refugee Act of 1980, annual admissions figures have ranged from a high of 207,116 in 1980, to a low of 27,100 in 2002." www.acf.hhs.gov