One of Trump’s most extreme proposals is ending birthright citizenship in America. This bill in Congress would enact it.

Republican Presidential candidate Donald Trump wants to end birthright citizenship. Currently the status quo policy in America, ever since the 14th Amendment was passed shortly after the Civil War, anybody born on U.S. soil is automatically made a citizen, even if neither of their parents are. About 300,000 children a year — roughly eight percent of new babies born in America each year — are to noncitizen parents, but are instantly citizens under the status quo.

There’s legislation in this Congress that would end the practice, enacting the same policy that Trump shocked the nation by calling for. But this legislation was introduced seven months prior to when Trump first announced his plan last August.

The legislation

The Birthright Citizenship Act, H.R. 140 and S. 45, would amend the Immigration and Nationality Act to say that somebody born in the U.S. is only a citizen if one of their parents is as well, or a “lawful permanent resident” or a noncitizen serving in the U.S. military.

The House version was introduced by Rep. Steve King (R-IA4), one of the most conservative members there. The bill was introduced on January 6, 2015, the very first day of the current Congress, indicating just how a high a priority it was to King. The bill has 49 cosponsors, all Republicans. It’s been referred to the House Judiciary Committee, specifically the Subcommittee on Immigration and Border Security, but has not yet received a vote.

The Senate version was introduced by Sen. David Vitter (R-LA) but has had a much more difficult time there, attracting zero cosponsors — not even any Senate Republicans have signed on. However, at least several Senate Republicans have publicly expressed ending birthright citizenship, including Rand Paul of Kentucky, Kelly Ayotte of New Hampshire, and Jeff Sessions of Alabama. Why they haven’t signed on to the bill is not clear.

If enacted, the law would certainly be brought to the Supreme Court. The 14th Amendment grants citizenship to those born “subject to the jurisdiction” of the United States, and it has never been settled exactly what that means.

What supporters say

Supporters argue that the status quo undermines national sovereignty and drains the American economy.

“Our nation must eliminate needless incentives that encourage illegal immigration and cost taxpayers significant amounts of money each year,” King says on his website’s issues page. “I do not believe it is in the best interest of our nation to continue tolerating the practice of illegal aliens giving birth to children in the U.S. in order to obtain citizenship for the child, then moving back to their country of origin with the hopes of achieving uninhibited access to our country for as many family members as possible.”

Trump put it more bluntly during a Republican debate last year. “”A woman gets pregnant. She’s nine months, she walks across the border, she has the baby in the United States, and we take care of the baby for 85 years. I don’t think so,” Trump said. “And by the way, Mexico and almost every other country anywhere in the world doesn’t have that. We’re the only ones dumb enough, stupid enough to have it.” On that point, Trump is correct: only 30 of the world’s 194 countries offer the equivalent of birthright citizenship.

Running mate Mike Pence also introduced legislation in 2009 to end birthright citizenship while in Congress, a bill which never received a vote. But when asked recently if Pence still stood by his 2009 position, he declined to say, saying he hadn’t thought about it recently.

What opponents say

But with the GOP deeply divided on the issue — with Republican presidential candidates split between those firmly in favor, those strongly opposed, and those expressing a middle ground — the Democratic Party has been uniformly opposed. They argue that it would be xenophobic and undercut the principle that everybody in America gets a fair shot.

Democratic presidential candidate Hillary Clinton, asked about it on the campaign trail, replied, “It’s hard to imagine being more out-of-touch or out-of-date. But all the over-the-top rhetoric does throw the choice in this election into stark relief.” President Obama has also expressed his support for birthright citizenship. (Although some would note that Obama’s belief apparently only extends to a certain level excluding certain island territories, with his administration currently fighting attempts for birthright citizenship in the U.S. territory American Samoa.)

One of the most prominent Republican supporters of birthright citizenship — and so an opponent of the bill — is Sen. Marco Rubio (R-FL), whose parents were not yet U.S. citizens when he was born in Florida. Rubio said of potentially changing the law: “Number one, I don’t think we can. Number two, while there is some interesting debate going on… that whole legalistic question, the prevailing belief is that, in fact, it says that anyone born in the territory of the United States, irrespective of the status of their parents, unless they’re diplomats, are U.S. citizens. That’s not going to change, and I don’t support changing that.”

This article was written by GovTrack Insider staff writer Jesse Rifkin.