The Trump administration is engaging in an immigration crackdown in South Texas — against people who have birth certificates showing they were born in the United States.

According to a Washington Post report published Wednesday by Kevin Sieff, immigration lawyers in the area are reporting that “hundreds, even thousands” of Latinos born near the US-Mexico border are being told that their birth certificates aren’t sufficient proof of US citizenship to get their passports approved or renewed.

They’re being subjected to ridiculous document requests like baptismal records, and insulting interview questions like “Do you remember when you were born?” Some are having their existing passports revoked and being thrown in deportation proceedings, or even being barred from reentering the United States when they attempted to come back from Mexico.

A lot of people (not least immigrants and other nonwhite Americans) have already come to the conclusion that the Trump administration lacks any respect for them as Americans or as people; in that context, the denial of passports to native-born citizens can look like racism at best and state violence at worst.

As a general rule, the Trump administration’s immigration actions aren’t shocking because they’re unprecedented power grabs. Instead, they’re efforts to aggressively use the existing powers the executive branch already has — powers that have simply been used with more restraint in the past.

This story is no exception. It’s an escalation of an effort started by past presidents. The Trump administration has shown a knack (and a fervor) for finding the parts of the immigration system that give the most power to the government, and bringing their full strength to bear on people who are already vulnerable. It’s doing that in South Texas right now.

This is a new round of assaults on a community that was already under scrutiny

The new wave of passport scrutiny is specifically targeted at Latinos in South Texas, born near the US-Mexico border in particular circumstances.

State Department representatives told the Washington Post that “the U.S.-Mexico border region happens to be an area of the country where there has been a significant incidence of citizenship fraud.” That sounds like a racist excuse — playing into suspicions that even Latinos who have been living in Texas since before it was America aren’t really American, and conflations of Latinos, immigrants, and unauthorized immigrants — but there is a particular history behind it.

In the second half of the 20th century, the federal government cracked down on midwives in South Texas for birth certificate fraud: signing a birth certificate attesting to delivering a baby on US soil, when the baby had actually been born across the border in Mexico.

Between 1960 and 2008, at least 75 midwives practicing in South Texas were convicted of fraudulent activities. (A 2008 Brownsville Herald article, also by Kevin Sieff, puts the number at 79.)

The problem, of course, is that those midwives also signed a bunch of birth certificates for children who really had been born on US soil. There aren’t easy ways to tell real US births from false ones — especially when most families in infrastructure-poor and poverty-stricken South Texas couldn’t necessarily afford hospital birth.

Confusing matters even further, some families reportedly got birth certificates saying their US-born children had been born in Mexico, to allow them to attend public schools there.(Before the last couple of decades, it wasn’t uncommon for families to travel frequently between the US and Mexico, or even split time between the two on a weekly basis.)

In 2007, the US changed the law: Starting in 2009, it would start requiring everyone coming to the US from anywhere in the Western Hemisphere (including American citizens returning from Mexico) to show a passport. As that change approached, area Latinos started to complain that their passports were being denied because their birth certificates were deemed suspicious — prompting an ACLU lawsuit.

The lawsuit was filed in 2008 (under the Bush administration) and settled in 2009 — with the two sides agreeing to a process by which passport denials to midwife-born applicants would be reviewed. One of the documents in the settlement was a sample letter requesting more information from the applicant to supplement the record.

Some of the items on the list were faintly ridiculous — including baptismal records or evidence of prenatal care, both of which were cited in the Post article — but others were straightforward, if often difficult, requests for school and employment records.

Even after the settlement, rejections of midwife-issued birth certificates continued. In 2012, CNN wrote an article about the phenomenon; in 2014, NPR program Morning Edition ran a segment. Both articles quote Jaime Diez, a lawyer also quoted heavily in the Washington Post piece. They also include accounts of people having their passports taken from them as they tried to enter the US, being harassed by Border Patrol agents, and being forced to agree to their own deportation.

What’s changed under Trump appears to be mostly the scope of the denials: according to the attorneys the Post spoke to, at least, there’s been a “surge” in new denials, as well as of people being actually put into deportation proceedings (something that Immigration and Customs Enforcement officials can choose to do when a passport is denied for absence of evidence of US birth, but don’t have to do).

Additionally, the government appears to have expanded its “suspicions” not just to birth certificates signed by midwives, but those signed by longtime South Texas obstetrician Jorge Treviño — who delivered thousands of babies, often in home births, before his death in 2015. (One lawyer told the Post that the government has an affidavit from an anonymous Mexican doctor alleging that Treviño falsified a birth certificate; Treviño, being dead, can’t answer the allegations.)

But perhaps most importantly, this is happening under President Donald Trump, who hasn’t exactly built up a record of goodwill among immigrants, US-born Latinos, or white liberals. And so the report has raised concerns not only about the harassment facing the particular passport applicants in South Texas, but about how broadly the Trump administration could challenge the citizenship — and voting rights — of other groups as well.

The Trump administration is pushing on the soft parts of the immigration system

Most Americans assume there’s a clear-cut line between legal immigrants and unauthorized immigrants; between noncitizens and citizens; between immigrants who have been naturalized and citizens who were born here.

The Trump administration often sparks outrage for doing things that appear to cross those lines: arresting unauthorized immigrants at their green-card interviews; starting an effort to comb old naturalization applications for fraud, in an effort labeled a “denaturalization task force” by the press; and, now, questioning the citizenship of people who have lived for decades as native-born US citizens.

But in all of these cases, the administration isn’t crossing an unprecedented bright line. It’s exploiting places where the boundaries between categories are murkier — often by building on what past administrations had already done. (It wasn’t the Trump administration that collected a list of “suspicious” midwives, for example.)

Generally, these boundary areas are where immigration officials show the most caution. They have discretion in who they pursue and who they don’t — at the margins, they’re most likely to use their discretion to show sympathy to people who’ve been living in the US and have roots here, even if they could be more aggressive in trying to push them out.

It’s possible that the government has changed its policy across the board on birth certificates issued by midwives or other “suspicious” practitioners — or even for people born in the US to non-US citizens more broadly — though there’s no evidence for that.

It’s also possible that the government hasn’t changed policies, and is just fighting more of the individual cases that fall under the process set down in the 2009 settlement. (The government maintains that there’s been no policy change to passport adjudication, for what that’s worth — and the attorneys who spoke to the Post don’t allege a particular change in policy.)

This is what makes Trump officials’ immigration policy different: not necessarily what they’re doing, but how aggressively they’re doing it.

The Trump administration doesn’t have to deny every (or even any) application from someone whose birth certificate was signed by a “suspicious” practitioner. But it is using the full extent of the power given it by law. It’s easier to put pressure on groups that have already been targeted because they’ve already been targeted.

Targeting passport applicants in South Texas isn’t necessarily a test run for an inevitable expansion to the widespread revocation of citizenship for Latinos or nonwhite Americans writ large, just as the denaturalization efforts don’t automatically call the citizenship of all naturalized Americans into question.

This remains true because, crucially, the people being targeted still have recourse to the legal system. Even the South Texans whose birth certificates are challenged, the Post says, typically end up winning their cases — they just have to appeal to the federal courts to do it, which takes money (in the thousands) and time.

But that’s the other thing about a strategy of pushing on those who are already marginalized: They’re the ones least likely to have the resources to overcome harassment, or the support to call for an end to the practice.