He's not alone in the GOP field. New Jersey Gov. Chris Christie said in a radio interview
last week that the birthright citizenship needs to be "reexamined," and Wisconsin Gov. Scott Walker told MSNBC
he supports ending it. Louisiana Gov. Bobby Jindal tweeted
on Monday evening that it should be curtailed. Kentucky Sen. Rand Paul introduced an amendment that would have restricted birthright citizenship in 2011
, but his position today hasn't been clarified.
South Carolina Sen. Lindsey Graham called it a "mistake" in 2010
-- and on Monday he lambasted
Trump's immigration plan but said citizenship may be an area where they agree, as long as the overall immigration system is reformed first.
On Tuesday, Florida Sen. Marco Rubio said he opposed repeal of the 14th Amendment. "I'm open to doing things that prevent people from coming to the U.S. to take advantage of 14th Amendment, but I'm not in favor of repealing it," he said at the Iowa State Fair.
Former Florida Gov. Jeb Bush echoed Rubio's sentiment at a campaign stop in South Carolina.
"This is a constitutionally protected right, and I don't support revoking it," Bush said when asked about the 14th Amendment right. "There's a way to use leadership to solve abuses, of people coming into the country having children so their children can become citizens. That's a legitimate problem and there's a targeted way you can deal with this. But to suggest that people born in this country are not United States citizens because they don't have this in the Constitution, I just reject out of hand."
The issue has come before the nation's highest court -- although the biggest cases on the topic were decided in the 19th century. But that hasn't kept lawmakers from seeking ways to change the current understanding of the key passage of the 14th Amendment, which was ratified in 1868:
"All persons born or naturalized in the United States, and subject to the jurisdiction thereof, are citizens of the United States and the State wherein they reside."
What is birthright citizenship?
The United States confers citizenship by what's referred as jus soli -- Latin for right of soil -- as opposed to jus sanguinis -- Latin for right of blood. The concept of making all children born in a territory a citizen of that territory dates back to English common law that was imported to the first American colonies. But in the 1857 Dred Scott v. Sandford decision, the Supreme Court held that birthright citizenship did not apply to the children of slaves.
After the Civil War, the citizenship clause was added to the 14th Amendment in order to make clear that all black Americans and freed slaves were in fact citizens, under to the Constitution.
The Supreme Court further upheld the interpretation that all children born in the U.S. are citizens (aside from those born to foreign diplomats and invading armies) in the 1898 decision in U.S. v. Wong Kim Ark. In that case, a man born to two Chinese parents who were living in the U.S. traveled to China for a brief visit before returning to the States, where he had spent his entire childhood, but he was denied entry. The high court held that he was a U.S. citizen, as were all children born to immigrants living in the U.S.
Is the U.S. unique in offering it?
According to an analysis
by the Center for Immigration Studies, which advocates for reducing immigration, 30 countries of the world's 194 have a policy of birthright citizenship, with the U.S. and Canada the only advanced economies to do so.
Why the controversy?
Republicans say that birthright citizenship needs to be changed to stem illegal immigration. They argue that having children become U.S. citizens is a motivating factor for immigrants to come into the country illegally, and that when the child reaches adulthood he or she can try to sponsor their parents for citizenship. The U.S. also rarely moves to deport parents of U.S. citizens, they say.
Critics of birthright citizenship also claim "birth tourism" is a troubling and growing concern. The Center for Immigration Studies this spring compared CDC data on children born to foreign mothers with Census data on foreign-born women reporting having a child, and concluded
there are about 36,000 birth tourists having children in the U.S. a year.
In 2010, the Pew Hispanic Center
estimated that 340,000 out of 4.3 million babies born in the U.S. in 2008 were the children of unauthorized immigrants, about 8 percent.
"There's no doubt that it's a growing phenomenon," CIS legal policy analyst Jon Feere said.
In 2010, though, PolitiFact found there wasn't much credence
to claims that there is a rampant "drop and leave" phenomenon of mothers having their child in the U.S.
How can it be changed?
There is a dispute over whether ending birthright citizenship is possible without a constitutional amendment.
Some critics of birthright citizenship say it could be changed by law, by defining what "subject to the jurisdiction thereof" means in the 14th Amendment. The provision thus far has only been interpreted to rule out children of diplomats, invading armies and, when the amendment was enacted, Native Americans, who would have had to give up their place on a reservation if they were automatically conferred U.S. citizenship.
One of the biggest political proponents of this position is Iowa Rep. Steve King, a Republican who has introduced legislation to restrict birthright citizenship to legal residents.
"If the Constitution required them to be citizens, anyone born on the United States, it would just say all persons born in the United States are American citizens," King told CNN in Iowa on Monday. "But the clause, 'and subject to the jurisdiction thereof', is the subject of a significant amount of legal scholarship ... Someone who comes in here illegally are not fully subject to the jurisdiction of the United States, they're not subject to being drafted, for example, so you can change it statutorily."
Immigration supporters say there's a reason the issue hasn't come up before the Supreme Court since 1898 -- and it's because it's settled.
"I feel like this is some kind of bad legal Groundhog's Day," said Karen Tumlin, managing attorney at the National Immigration Law Center. "These proposals come up perennially, but there is no gray area here: This is very clear language in a constitutional amendment...We don't alter the constitution lightly in this country."
Which side is right, ultimately would have to be determined by the Supreme Court, Feere said.
Has it been tried before?
Lawmakers have been introducing constitutional amendments and legal clarifications like King's for decades.
In 1993, Nevada Sen. Harry Reid -- now the Senate Minority Leader -- espoused ending birthright citizenship, introducing legislation
to do so. Though his past position is often cited by Republicans supporting the move, including by Trump in his policy paper, Reid later disavowed his actions. In a 2006 speech, he called
it "the biggest mistake I ever made."
In the current Congress, King has introduced his legislation in the House, and Louisiana Republican Sen. David Vitter has done the same in the Senate. Neither bill has gone anywhere beyond introduction, as is true of virtually all past legislative attempts to end birthright citizenship.