Legal immigrants get a permanent resident card. Immigrants can come to the U.S.A. with a work visa, where they are allowed to stay while they work, a H-1B, where the immigrant is studying to get a professional level job, become a citizen, or get a L-1, which is an inter-company transfer. Legal immigrants apply for a green card to become permanent residents. Immigrants can apply for political asylum.

Illegal immigration causes many problems. Illegal immigration can be done many ways. One way is for an immigrant to enter the country without legal permission. Another way is for an immigrant to enter the country legally with a visa and then not leaving...