Before Teddy Kennedy’s 1965 immigration act extended “civil rights” to the entire world, immigrants to America were far more varied. Seven countries each provided 5 percent or more of the total number of immigrants each year — Italy, Germany, Canada, the United Kingdom, Poland, the Soviet Union, and Mexico.

By 2000, Mexico was the only country supplying more than 5 percent, accounting for nearly a third of all immigrants to the United States.