The U.S. Constitution does not define a federal power over immigration. Instead, courts have considered it an authority belonging to an independent nation. United States immigration law has developed extensively over the years. Immigration happens when a person moves to a new country with the intention of living there.

The Constitution creates a government of specific powers. The powers of each branch of government are listed out and detailed. The Constitution delegates to Congress the power "(t)o establish a uniform Rule of Naturalization … throughout the United States." Thus, the Constitution gives Congress the power to determine which foreigners can become citizens.

The Constitution, however, is silent about immigration. It does not say that the federal government has the power to exclude or remove noncitizens from the United States. Nevertheless, the courts have allowed the federal government to exercise such a power.

As early as 1798, Congress acted on immigration. It passed laws allowing the president to take action. The president could imprison or deport immigrants. They had to have immigrated illegally, and also be considered dangerous (Alien Friends Act of 1798). Another law changed the residency requirement for naturalization. It increased from five to 14 years (Naturalization Act of 1798).

Still, for most of the nation's first century, the source of Congress' power to act on immigration was not relevant. Immigrants were allowed in without restriction. However, in 1875, Congress barred the immigration of convicted criminals. In 1882, it no longer allowed the immigration of people who were very poor. It also barred those with mental illnesses and disabilities from immigrating.

At One Time, Chinese Were Excluded

Also in 1882, Congress passed the Chinese Exclusion Act. This law kept Chinese people from immigrating to the U.S. In the legal arguments over this law, the Supreme Court clarified a basis for federal power to regulate immigration.

In Chae Chan Ping v. United States, 130 U.S. 581 (1889), the Supreme Court stated that Congress can exclude noncitizens from the United States. The power to do so is part of its independence as a country. If it couldn't exclude people, then it would not be independent.

In Fong Yue Ting v. United States, 149 U.S. 698 (1893), the Supreme Court further held that a nation has the right to expel foreigners if they have not yet been naturalized. This right is "absolute."

The Supreme Court has ruled deportation is exclusively a federal power. In other words, states cannot make their own immigration laws.

Since the 1880s, Congress has exercised its power over immigration extensively. In the 1920s, immigration was based on a quota system. Immigration from each nation was limited. This limit was based on population figures from past U.S. census figures. As a result, more immigration was allowed from Northern and Western Europe than other areas of the world.

Federal Powers Were Generally Established in 1952

Today, the federal power over immigration is set forth in the Immigration and Naturalization Act. It became law in 1952 and kept certain exclusions.

Amendments to that law in 1965 got rid of national origin quotas. Instead, the law emphasized family reunification. If an immigrant had family members who had entered the U.S. legally, that immigrant had a better chance of being allowed in. Amendments that followed in 1986, 1990, and 1996 granted partial amnesty to immigrants who were undocumented. They also increased levels of immigration. The Patriot Act of 2001 toughened background checks for admittance to the United States.

Historically, the United States also has been the global leader in accepting refugees. These are people who can show they are threatened in their home country and fear returning there. That may be because of their race, religion, or political beliefs.

U.S. policy on immigration has varied over the years. Sometimes it has been more open and sometimes more restrictive. Some of this confusion has been due to the unclear constitutional basis for federal authority over immigration. The Constitution does not exactly set forth which branch of government is in charge. Each branch has, at various times, tried to assert its authority.