A number of peripheral changes were made in legislation enacted between 1957 and 1964.
A major revision, origin ally proposed by President Kennedy and ultimately enacted in 1965, abolished the national origins quota system and discriminations against Asians, and allocated visas on a first come, first served basis, subject to preferences for relatives of American citizens and persons with special skills.
Another major revision, adopted in 1976, incorporated in the basic law a separate quota for aliens from the Western Hemisphere, originally prescribed by the 1965 law.