The U.S. immigration enforcement system wasn’t designed for today’s regional and global flows of people.

American immigration policy is enforced by a sprawling bureaucracy rebuilt in the aftermath of 9/11 from the bones of a 20th-century system designed to modulate the flow of temporary workers from Mexico.

The resulting Department of Homeland Security (DHS) hosts three major immigration agencies with a workforce weary of radical policy changes from administration to administration.

Since their creation in 2003, the DHS agencies of Customs and Border Protection (CBP), Immigration and Customs Enforcement (ICE) and United States Citizenship and Immigration Services (USCIS) have faced partisan culture shock: the terrorism prevention focus of the Bush administration and the overtly restrictionist policies of Trump, alternating with the more liberal strategies of the Obama and Biden administrations.

“In some ways, the bigger fact here that is really difficult for these agencies is whiplash. And it is the fact that with each administration, there have been really sharp changes in policy, and that is very difficult for large organizations of any kind,” said Doris Meissner, who ran the Immigration and Naturalization Service under former President Clinton and now heads the U.S. Immigration Policy Program at the Migration Policy Institute.

“But certainly, these organizations that are dealing with such controversial issues, those really sharp changes from administration to administration are probably the more difficult thing to live with.”

Those changes have been so abrupt as to affect the agencies’ entire mission statements.

In 2018, under President Trump, then-USCIS Director Francis Cissna announced a new such statement, dropping the phrase “nation of immigrants” and removing the term “customers” for the foreign nationals who petition the agency for work permits, changes in immigration status and naturalizations.

Last year, the Biden administration quietly introduced a new, brief mission statement, dropping Cissna’s national security-focused motto without returning to the original, wordy language: “USCIS upholds America’s promise as a nation of welcome and possibility with fairness, integrity, and respect for all we serve.” 

The whiplash is more than skin-deep, and it affects leadership at all levels.

ICE hasn’t had a Senate-confirmed director since the Obama administration, and CBP has been led by an acting commissioner for four of the last six years.

“It’s affected the bigger vision piece,” said an official who asked for anonymity to speak candidly.

“But the underlying function has been moving toward professionalization.”

Trump, for one, weaponized the difficulty of Senate confirmations, spending nearly half his presidency with an acting DHS secretary.

“I like acting. It gives me more flexibility. Do you understand that? I like acting. So we have a few that are acting. We have a great, great Cabinet,” Trump said in 2019, shortly before Kirstjen Nielsen, Trump’s last Senate-confirmed DHS head, quit the job.

And Trump used that flexibility to staff top roles in immigration agencies with prominent names from the restrictionist movement, drawing vocal support from staff who supported hawkish policies.

“There definitely were aspects of the law enforcement culture and voices, especially the unions from within CBP and ICE, that were strongly strongly encouraging of all of those policies,” Meissner said. 

“But there also were people in those agencies that were marginalized during that period of time, and were deeply offended by the rhetoric and by the very, very extreme characterization of migration and migrants.” 

While President Biden did not entirely give the keys to the activist wing of immigration advocacy, he has employed key activists in top White House advisory positions.

Biden picked Homeland Security Secretary Alejandro Mayorkas because of his strong law enforcement resume and endorsements from former Bush-era secretaries Tom Ridge and Michael Chertoff, but those credentials were bunk to most Republicans of the Trump era.

Mayorkas’s role as one of the architects of the Obama-era Deferred Action for Childhood Arrivals program, and relentless GOP attacks on the administration’s border policies, have turned the secretary into a lightning rod, often facing impeachment threats from House Republicans.

But looking inward, Mayorkas has his hands full at the helm of an agency with about 260,000 employees.

The immigration components of the DHS have a history of low morale, in part because officers and agents are tired of changing directions.

That exhaustion is most evident in the Border Patrol, a component of CBP, where the job doesn’t always match the training.

In part, that’s because of generational shifts: Officers hired before 9/11 were trained to cover large swathes of wilderness looking for surreptitious border crossings, the next generation was attuned to terrorism prevention, and over the last decade, officers have grown into the work amid a global mass migration phenomenon.

That’s made the job more often about processing asylum seekers than protecting “the line,” though Border Patrol recruitment ads would indicate otherwise.

“It’s very clear that the Border Patrol culturally believes that it’s being kept from carrying out the law enforcement mission for which they were trained and for which they are in border enforcement,” said Meissner, adding that the Border Patrol is being “very innovative” in adapting to the role required by conditions on the ground.

“What they don’t see is how great they’re actually doing,” said the official who asked for anonymity.

Administration officials say they are bullish about the state of ICE and CBP, including the Border Patrol.

Both agencies are better funded, equipped and more robust than ever, though the Border Patrol has a chronic staff retention issue.

And both are expanding their footprint. ICE, for instance, conducted a repatriation flight to Venezuela on Wednesday — the first since Biden administration officials reached a deal with the Maduro regime earlier this month.

The expansion of deportation flights won’t endear the Biden administration to its allies in immigration advocacy, but internally, it’s seen as a victory for the proper functioning of the DHS.

Officials are not quite as upbeat over the future of the USCIS, an agency primarily funded by immigrant application fees. Aside from its financing woes, it is stuck implementing a legal immigration system that the administration and its allies agree is outdated.

Immigration laws “are mismatched” to the economic needs of both migrants and the U.S. labor market, the official said.

That mismatch creates more unpaid work for the USCIS — humanitarian applications such as asylum don’t incur fees — and overloads CBP at the border with asylum claimants who, under a different legal framework, could have applied for a fee-incurring work visa and flown directly to their final destination.

Advocates understand that Congress has not budged on immigration law for decades, but they say the administration could amp up immigration processing, both at the DHS and in the Department of Justice’s Executive Office for Immigration Review — immigration court.

“The two biggest hurdles to a functioning system are pathways that meet the needs of the country — and that’s a matter of, you know, I think that’s a matter that’s more of a role of Congress than the agencies that are executing and implementing our laws. So I don’t think that the agencies are to blame there,” said Krish O’Mara Vignarajah, president of the Lutheran Immigration and Refugee Service.

“The other piece is just staffing. We live in, obviously, we live in an economy that reflects the job market. We don’t have nearly the staff that we need, whether we’re talking about asylum officers or immigration judges, and that is where I think the agencies could play a more proactive role.”

That’s a point of contention between the Biden administration and advocates.

Administration officials say asylum is being unfairly abused by economic migrants, and they emphasize the need for deterrence paired with expanded legal pathways.

“I think that the lesson we ought to have learned by now is that deterrence doesn’t work when desperate people are fleeing for their lives,” Vignarajah said.

With reforms to U.S. immigration laws and short-term solutions to poverty and instability in the Americas seemingly out of reach, advocates say success in addressing the present humanitarian challenge will ultimately be judged on higher standards.

“Do we have a system that reflects our role as a global humanitarian leader? Do we have a system that meets our economic and national security needs? And do we have a system that is true to our history in part as a nation of immigrants?” Vignarajah said.

Updated at 9:42 a.m. ET