Amid outcry over the “zero tolerance” immigration policy implemented by President Donald Trump’s administration in April, conservative commentators and his head of Homeland Security have sought to downplay the practice of separating families who cross the border illegally as nothing new.

“The Obama administration, the Bush administration all separated families,” Department of Homeland Security Secretary Kirstjen Nielsen told reporters at the White House on Monday. “They absolutely did. They did — their rate was less than ours, but they absolutely did do this. This is not new.”

Matt Schlapp, chairman of the American Conservative Union, made a similar point on Fox News on Friday.

“You know what’s ironic?” he said. “It’s the same way Barack Obama did it.”

But immigration advocates and former Obama administration officials say that’s just not true: The Obama administration did not have any kind of widespread practice of separating children from their parents. Trump’s policy aims to prosecute every single illegal border crossing, including asylum seekers. The government separates children from their parents or legal guardians because the adults have been referred for prosecution for illegal entry into the United States.

The idea that this is simply a continuation of an Obama-era practice is “preposterous,” said Denise Gilman, director of the Immigration Clinic at the University of Texas Law School. “There were occasionally instances where you would find a separated family — maybe like one every six months to a year — and that was usually because there had been some actual individualized concern that there was a trafficking situation or that the parent wasn’t actually the parent.”

Once custody concerns were resolved, “there was pretty immediately reunification,” Gilman told NBC News. “There were not 2,000 kids in two months — it’s not the same universe,” she added.

The Trump administration separated 1,995 children from 1,940 adults from April 19 to May 31, a spokesman for the Department of Homeland Security said Friday, a period in which the “zero tolerance” policy was in effect.

Jeh Johnson, who served as homeland security secretary under Obama, said he did not separate children and parents despite the enormous surges of unaccompanied minors and families that came across the border in 2014 fleeing Central American violence.

“In three years on my watch, we probably deported or returned or repatriated about a million people to enforce border security. One of the things I could not do is separate a child from his or her mother, or literally pull a mother from his or her arms,” Johnson said on MSNBC last week. “I just couldn’t do it.”

Obama’s top domestic policy adviser, Cecilia Muñoz, said the Obama administration did consider a similar policy, but determined it heartless.

“The agencies were surfacing every possible idea,” Muñoz told The New York Times in an interview recently. “I do remember looking at each other like, ‘We’re not going to do this, are we?’ We spent five minutes thinking it through and concluded that it was a bad idea. The morality of it was clear — that’s not who we are.”

The Obama administration did, however, detain families together — some indefinitely — in hopes of deterring future migrants back in 2014, earning protests and public outrage at the time.

“Family separation just adds injury to the insult of detention,” said Bradley Jenkins, manager of the Board of Immigration Appeals Pro Bono Project at CLINIC, the Catholic Legal Immigration Network Inc. He argued the detention of asylum seekers is “unnecessary,” and that Obama-era detention centers were concerning, too.

During the Obama administration, courts intervened in several cases in which families were detained together. The detention of migrants could not be used as an effort to deter asylum seekers, according to one ruling. According to another, the detention of minors with their parents ran afoul of the 1997 Flores settlement, a ruling that set standards for the detention of minors by prioritizing them for release to the custody of their families and requiring those in federal custody to be placed in the least restrictive environment possible.

On Tuesday, the Trump administration said they are looking for a legislative change to that legal precedent on how the government treats children in immigration custody.

“In each and every one of our negotiations in the last 18 months, all the immigration bills, we asked for resolution on the Flores settlement that is what we view requires 20 days before you have to release children and basically parents been released with children into society,” White House Legislative Affairs Director Marc Short told reporters.

It’s unclear if the Trump administration seeks authority to detain children long-term, or would support another method of keeping families together during prosecution.

Fact check: Did Obama administration separate families?