What is the 14th Amendment and how does it apply to birthright citizenship?
President Donald Trump issued an executive order on Monday evening targeting automatic citizenship for U.S.-born children of immigrants in the country illegally, contrary to the 14th Amendment.
The order was part of a flurry of executive action Trump took on the first day of his second term.
"The federal government will not recognize automatic birthright citizenship for children of illegal aliens born in the United States. We are also going to enhance vetting and screening of illegal aliens," said a Trump official in a briefing on Monday.
Ending birthright citizenship was a campaign promise for Trump, emphasized in a post-victory interview with NBC News.
Trump has falsely claimed that the U.S. is the only country that grants citizenship through birth, but a Law Library of Congress report shows more than 30 countries worldwide grant citizenship by birth.
The executive order is part of a strict immigration strategy from the second Trump administration, which suspended the CBP One app that allowed migrants to apply for immigration appointments.
"All illegal entry will be immediately halted and we will begin the process of returning millions and millions of illegal aliens back to the places from which they came," Trump said during his inauguration speech.
What does the Constitution say?
The 14th Amendment was ratified in 1868 after the Civil War, granting citizenship and rights to formerly enslaved people.
Section 1 states, "All persons born or naturalized in the United States, and subject to the jurisdiction thereof, are citizens of the United States and of the State wherein they reside."
The clause, "subject to the jurisdiction thereof," most commonly excludes children born to foreign diplomats.
Birthright citizenship for foreigners has been affirmed by the Supreme Court despite being challenged many times, according to the American Immigration Council.
Libertarian think tank Cato Institute said ending guaranteed birthright citizenship is an "unorthodox view" not supported by the vast majority of constitutional lawyers.
When does the order go into effect?
A coalition of 18 states sued Trump and federal agencies in U.S. District Court in Massachusetts Tuesday, seeking to block the order on grounds that it violates the Constitution. The ACLU filed a separate legal challenge in New Hampshire on behalf of immigrant advocacy organizations.
Under Trump's order, after Feb. 19, U.S.-born babies must have at least one parent who is a U.S. citizen or lawful permanent resident in order to gain citizenship. The lawsuits could delay implementation pending their resolution.
Ending birthright citizenship a campaign pledge
The ending of birthright citizenship was a key piece of the Trump campaign's Agenda47 policy platform.
The campaign said the administration would clarify the amendment, so it is understood "that U.S. Citizenship extends only to those both born in AND 'subject to the jurisdiction' of the United States."
This story has been updated with new information
Contributing: Lauren Villagren
This article originally appeared on USA TODAY: What is the 14th Amendment and birthright citizenship?