At least four organizations involved in Project 2025, a sprawling effort to provide policy and staff to a future Trump administration, have spent years arguing against birthright citizenship — a cornerstone of U.S. immigration policy that is guaranteed by the 14th Amendment. 

Project 2025 is organized by conservative think tank The Heritage Foundation — which has opposed birthright citizenship for decades — and has more than 100 right-wing groups on its advisory board. Of those, high-ranking figures at both the MAGA-aligned think tank The Claremont Institute and the Center for Immigration Studies, which was founded by the nativist John Tanton, also oppose birthright citizenship. So does former Trump adviser Stephen Miller; he recently delisted his organization America First Legal from Project 2025’s board, but his fingerprints are all over it. 

Although ending birthright citizenship is an extreme and unpopular proposal, these are not fringe groups. Heritage has been at the center of the conservative policy ecosystem for decades. In a 2018 fundraising email recently unearthed by Media Matters, Heritage bragged, “President Trump has already embraced 64% of our recommendations.” Miller is expected to exert even more control under another Trump administration than during Trump’s first term. Claremont is home to at least two former Trump advisers who oppose birthright citizenship — attempted coup participant John Eastman and Michael Anton, who wrote an op-ed for The Washington Post on the topic. Claremont also serves as a clearinghouse for right-wing media figures who move through their influential fellowship programs. CIS and other nodes of the Tanton network were instrumental in making policy and staffing the Department of Homeland Security under Trump.

As the American Immigration Council explains, the guarantee of citizenship for people born on U.S. soil has been a bedrock of Constitutional law for more than 150 years. And as AIC argued more than a decade ago, ending birthright citizenship wouldn’t slow unauthorized immigration. The conservative argument fails on its own merits but succeeds in advancing Project 2025’s broader anti-immigrant agenda. 

Conservatives have taken aim at birthright citizenship since the early 1990s, but examining the roles the four groups below have played since the turn of the millennium helps to explain how this issue has evolved from the fixation of a few well-placed cranks into conventional wisdom in the Republican Party.

The Heritage Foundation

As lead organizers of Project 2025, Heritage deserves pride of place in analyzing the right’s long campaign against birthright citizenship, not least because the think tank has been hammering the argument for nearly two decades.

In 2006, Heritage published a report by then-senior research fellow John Eastman — the same John Eastman who, as mentioned earlier, would later go on to try to help Trump overturn the results of the 2020 election while at Claremont — arguing against birthright citizenship. 

“It is today routinely believed that under the Citi­zenship Clause of the Fourteenth Amendment, mere birth on U.S. soil is sufficient to obtain U.S. citizen­ship,” Eastman wrote. “However strong this commonly believed inter­pretation might appear, it is incompatible not only with the text of the Citizenship Clause (particularly as informed by the debate surrounding its adoption), but also with the political theory of the American Founding.”

Eastman’s memo goes on to offer selective misreadings of the 14th Amendment and subsequent case law, arguments that Anton and others would later revive — only to be repeatedly debunked by mainstream outlets. The libertarian magazine Reason got in on the action too. 

The issue gained new salience in 2018, when then-President Trump repeated his pledge to end birthright citizenship via executive order. Heritage got the memo. On the same day Trump made his comments, Heritage republished a piece from 2011 under the headline “​​Birthright Citizenship: A Fundamental Misunderstanding of the 14th Amendment.” A week later Heritage had a new entry: “The Bane of Birthright Citizenship.” Subsequent posts were no more subtle. “End Birthright Citizenship for Illegal Families,” read a typical offering.

The Claremont Institute

What triggered Trump’s promise? He made his remarks in an October 2018 interview with Axios, which noted at the time that former Trump official Michael Anton had written an op-ed for The Washington Post in July of that year calling for an end to birthright citizenship. Anton, a senior fellow at Claremont, was, in the words of Vox’s Dara Lind, “shellacked” across the political spectrum for his poor scholarship and rhetorical sleight of hand. (For a sense of how universally despised Anton’s op-ed was at the time, note that even the right-wing blog The Federalist called the argument “intellectually and morally bankrupt.”) 

As the Post later clarified in a note appended to Anton’s piece, he’d inserted a bracketed “or” into a quote about the intent of 14th Amendment, which many historians believe changed the line’s meaning. 

The quote comes from Michigan Sen. Jacob Howard, one of the amendment’s original supporters, who argued that the citizenship clause exempts “persons born in the United States who are foreigners, aliens, who belong to the families of ambassadors or foreign ministers.” Anton added an “or” between “aliens” and “who,” which, as Lind explained, appeared to change Howards’ meaning from saying the amendment excluded “only people who belong to a diplomatic family” to excluding “all foreigners and all aliens.” 

Anton’s two inserted letters are doing a lot of misleading work, and he wasn’t even original in his sophistry. The Post’s clarification note links to other “writers” who had “made the same assertion” regarding the added word. The paper provided two supporting citations, one of which came from — wait for it — Claremont’s John Eastman, who in 2015 had written an article for the National Review that also included the deceptively added “or.” 

Writing in The Atlantic, constitutional law professor Garrett Epps further excoriated Anton’s “constitutional equivalent of flat-earthism,” noting that his article relies heavily on the work of political scientist Edward Erler — senior fellow and member of the board of directors at The Claremont Institute. 

The phrase “garbage in, garbage out” comes to mind, and Anton wasn’t done shoveling. After a nearly universally negative response to his article, he retreated to the friendlier confines of The Claremont Review of Books to pen “Birthright Citizenship: A Response to My Critics,” a lengthy rehashing that threw still more refuse at the wall to see what sticks. And because everyone loves a team up, that September Anton and the Claremont Institute joined — who else — The Heritage Foundation for a panel called: “The Case Against Birthright Citizenship.”

In case the racism undergirding opposition to birthright citizenship isn’t obvious, an episode from 2020 will perhaps put the issue to rest. After then-candidate Joe Biden named then-Sen. Kamala Harris as his running mate, Newsweek published an op-ed challenging her eligibility on the grounds that she was “​​not entitled to birthright citizenship under the 14th Amendment as originally understood,” — even though she was born in Oakland, California. Readers widely interpreted it as the latest expression of the racist “birther” conspiracy theory previously leveled against President Barack Obama. The author of that op-ed was none other than John Eastman.

Center for Immigration Studies

If Heritage and Claremont are the higher-profile opponents of birthright citizenship, the Center for Immigration Studies — which the Southern Poverty Law Center has designated as a hate group — is the workhorse that keeps the issue percolating in the conservative policy world.

In 2010, CIS’ Jon Feere wrote a white paper called: “Birthright Citizenship in the United States: A Global Comparison.” Although Feere discusses the 14th Amendment and Howard’s quote, he foregrounds decidedly more nativist concerns: “chain migration,” “birth tourism,” and the supposed “burden” unauthorized immigrants place on the social safety net (a common but false trope). 

Since 2010, CIS has published at least 70 posts under the tag “Birthright Citizenship” on its website. One key entry, a companion piece of sorts to Feere’s initial offering, came in November 2018 in response to Trump’s Axios interview. In “Birthright Citizenship: An Overview,” CIS’ Andrew Arthur argues that birthright citizenship “remains an open question,” and that “the costs of births for the children of illegal aliens is staggering.” (Numerous studies have shown undocumented immigrants to be net contributors to the economy.)

Arthur concluded that if the Supreme Court were eventually to roll back birthright citizenship, “U.S. law would be brought in line on this issue with the policies of many of our major allies, and many other industrial powers.” He continued, “The taxpayers of the United States would also save the costs of providing government benefits to those erstwhile U.S. citizens.”

Like with Heritage and Claremont, CIS’s nativism has a way of reproducing itself in the conservative policy world, thanks to another SPLC-designated extremist named Stephen Miller.

America First Legal

Stephen Miller is known as a leading advocate of some of Trump’s most xenophobic policies, including the administration’s “Muslim ban” and its family separation policy. It should come as no surprise then that in August 2019 Miller — then a White House senior adviser — told Fox News that the Trump administration was “looking at all legal options” to end birthright citizenship. 

Four months later, Rolling Stone revealed a series of emails between Miller and Jon Feere, who at the time was serving as a senior adviser in Immigration and Customs Enforcement. Feere — no longer at CIS, though he would return in 2021 — was Miller’s man at ICE, and although the heavily redacted emails don’t appear to reference birthright citizenship, Feere was so closely associated with eliminating it that Rolling Stone highlighted his published work on the subject near the top of its report. 

After Trump’s defeat in 2020, Miller founded America First Legal, a conservative advocacy group that bills itself as the right's answer to the American Civil Liberties Union. Although it doesn’t appear that AFL has taken up birthright citizenship, the same can’t be said for Miller. On at least four occasions, Miller has posted content disparaging of birthright citizenship on X (formerly Twitter).

Last December, he used scare quotes to refer to birthright citizenship in a post otherwise advocating for increased immigrant detention. In January, he pushed the racist “great replacement” conspiracy theory, writing that Biden’s immigration policy was “to import a new electorate & disenfranchise US citizens,” which explained his “stalwart opposition to ending birthright citizenship.”

A few weeks later, Miller was back at it. “Remember: sealing the border is half the conversation,” Miller wrote. “The other half is removing the innumerable millions Biden has resettled (and ensuring their children are not granted “birthright” citizenship).”

In March, Miller responded to a post from a right-wing account to insinuate — again, falsely — that immigrants are a drain on society.

Crucially, Trump and Miller are still in lockstep on the issue. Last November, The New York Times reported that Trump “would try to end birthright citizenship for babies born in the United States to undocumented parents.” 

Miller, never one for understatement, made a promise — or a threat. “Any activists who doubt President Trump’s resolve in the slightest are making a drastic error: Trump will unleash the vast arsenal of federal powers to implement the most spectacular migration crackdown,” he told the Times.

The cranks have their moment

Although Project 2025’s policy book doesn’t mention ending birthright citizenship, the energy these four groups or their leaders have devoted to the issue suggests that it will be a priority under a second Trump administration. It’s not entirely clear exactly how popular the issue is with Republican voters. A 2018 poll from the Public Religion Research Institute found that 67 percent of Republicans favored changing the Constitution to end birthright citizenship. A more recent survey from Axios placed that number at 46 percent of Republicans. 

Whatever the specific breakdown, Republican politicians and candidates have increasingly adopted the issue. Last July, Rep. Matt Gaetz (R-FL) introduced a bill to eliminate birthright citizenship for children of undocumented immigrants. This June, Sen. Tom Cotton (R-AR) introduced similar legislation. As part of Florida Gov. Ron DeSantis’ doomed presidential campaign, he pledged to “take action to end the idea that the children of illegal aliens are entitled to birthright citizenship if they are born in the United States." So did former Republican presidential candidate Vivek Ramaswamy. Former South Carolina Gov. Nikki Haley said she was against birthright citizenship for “people who've entered our country illegally,” but not in all cases. 

The issue, it seems, is not going away. In this recent history, Eastman, Feere, and Anton have all played outsized roles — not to mention Miller, who remains Trump’s immigration-whisperer. All four are central to Project 2025, which in turn is intended to serve as a specific and detailed roadmap for what another Trump term would look like. The threat these figures pose to a cornerstone of U.S. immigration policy is plain, their shoddy scholarship notwithstanding.