Explain mexico and canada's immigration policy!

Canada and Mexico’s importance to the United States is more than simply a border-state phenomenon. The trading relationship between United States and Canada represents the largest bilateral flow of income, goods, and services in the world. Meanwhile, Mexico is the United States’ second largest trading partner. Between NAFTA coming into effect and 2003, two-way trade between Canada and Mexico more than doubled.

The temporary visa category created for Mexican and Canadian NAFTA Professional Workers enabled 92,951 Canadians and 2,571 Mexicans to enter the United States on visas in 2001. In 2002, Mexico was the country of origin of the largest number of legal immigrant admissions to the U.S, and Mexicans represented about 29.8 percent of the total foreign-born population. In comparison, Canadian immigrant admissions were only 1.8 percent of total legal admissions.