On Monday, Sen. Kamala Harris called on Homeland Security Secretary Kirstjen Nielsen to resign, saying she had misled the public about the Trump administration’s apparent practice of splitting up families at the border. Harris cited a tweet from over the weekend in which Nielsen said that the government had no such policy.

We do not have a policy of separating families at the border. Period. — Secretary Kirstjen M. Nielsen (@SecNielsen) June 17, 2018

Harris might confused about what Nielsen meant here because over the past few days, a number administration officials—including Nielsen herself—have said different things about the apparent practice.

In an interview published with the New York Times on Saturday, Trump senior policy adviser Stephen Miller said that separating families was a “simple decision” and necessary to send the message “that no one is exempt from immigration law.”

Last week, Jeff Sessions cited a bible verse famously used to justify slavery to defend the apparent current practice.

Trump had previously—and untruthfully—blamed Democrats for the apparent practice, but on Monday he seemed to at least acknowledge that the administration had some part in it, citing his desire to prevent the U.S. from becoming like Europe as part of his rationale.

The people of Germany are turning against their leadership as migration is rocking the already tenuous Berlin coalition. Crime in Germany is way up. Big mistake made all over Europe in allowing millions of people in who have so strongly and violently changed their culture! — Donald J. Trump (@realDonaldTrump) June 18, 2018

We don’t want what is happening with immigration in Europe to happen with us! — Donald J. Trump (@realDonaldTrump) June 18, 2018

Children are being used by some of the worst criminals on earth as a means to enter our country. Has anyone been looking at the Crime taking place south of the border. It is historic, with some countries the most dangerous places in the world. Not going to happen in the U.S. — Donald J. Trump (@realDonaldTrump) June 18, 2018

CHANGE THE LAWS! — Donald J. Trump (@realDonaldTrump) June 18, 2018

It is the Democrats fault for being weak and ineffective with Boarder Security and Crime. Tell them to start thinking about the people devastated by Crime coming from illegal immigration. Change the laws! — Donald J. Trump (@realDonaldTrump) June 18, 2018

Chief of Staff John Kelly as recently as last month, meanwhile, described the practice as a “deterrent.”

On Monday, Nielsen herself seemed to acknowledge some sort of policy that led to the separation of parents from children. “We do not have the luxury of pretending that all individuals coming to this country as a family unit are in fact a family,” she said. “We have to do our job, we will not apologize for doing our job.”

As former White House Director of Communications Anthony Scaramucci said on Monday, these seemingly contradictory messages make the administration’s position difficult to decipher:

You can’t simultaneously argue that family separation isn’t happening, that it’s being used as a deterrent, that the Bible justifies it and that it’s @TheDemocrats fault. @POTUS is not being served well by his advisors on this issue. — Anthony Scaramucci (@Scaramucci) June 18, 2018

There’s likely a reason, though, why Nielsen has insisted categorically that no such policy exists. That reason is that such a policy would almost certainly violate the due process clause of the Constitution. In rejecting the government’s request to dismiss an ACLU lawsuit challenging the practice earlier this month, District Court Judge Dana Sabraw opined that a policy of indefinite family separation would be “brutal, offensive, and fails to comport with traditional notions of fair play and decency” and a “clear” violation of the “constitutional right to family integrity.” The judge, who is yet to rule on the merits of whether or not child separation is actually in fact what’s taking place, applied that logic equally to asylum seekers who have presented themselves lawfully at a port of entry and those who have been prosecuted for illegal entry and served their time. Those who had applied for asylum at a port of entry and saw their children taken away without any apparent lawful basis, as well as asylum seekers who had seen their children separated lawfully while they were detained for immigration offenses and had served their sentences were “on equal footing … for purposes of pursuing [a] due process claim,” the judge ruled.

That means the judge has written that indefinite child separation of asylum seekers—even in cases where a parent had been convicted of illegal entry—would be unconstitutional if it were happening. So in order to keep the practice going, the government has to deny publicly that it is in fact happening, as Nielsen did over the weekend.

As my colleague Mark Joseph Stern noted last week, in that failed motion to dismiss the due process grounds of the ACLU lawsuit, the government acknowledged it was making the choice to separate families, justifying it as an unreviewable “discretionary” decision. In that legal brief, the Department of Justice argued it was in its discretion to both indefinitely separate parents who had been convicted of the crime of illegal entry and those who had lawfully sought asylum by presenting their family at a port of entry. “ICE’s discretionary […] decision to detain an alien in a particular facility is not judicially reviewable,” the government argued. This is essentially an acknowledgment that the decision to hold families separately is a choice that Donald Trump’s government is making.

Evidence is piling up of what that looks like in practice. The ACLU lawsuit is full of declarations, including from parents who presented themselves lawfully at a U.S. port of entry, describing child separation. On Monday, Sen. Dianne Feinstein reported that 2,342 children had been separated from their parents at the border between May 5 and June 9. The Washington Examiner reported that—including children who arrived at the border by themselves—the administration could be holding 30,000 undocumented immigrant children by August. And for those who are willing to allow themselves to experience what child separation sounds like in practice, ProPublica has published an audio recording of one such separation taken from inside a U.S. Customs and Border Protection facility.