Debates about federal policy are often hindered by the fact that it’s frequently hard to obtain real-time data on what’s happening in the country. Some of that is mechanical, a function of having to gather information from across a huge geographic area for a nation with more than 330 million residents. Some of it is institutional, with a federal bureaucracy that is slower to embrace quick data deployment compared with the private sector.

That lag time leads to situations like the one last month, when critics of the Biden administration pointed to what they presented as a massive surge in migration from Mexico while the administration and many of its defenders sought to play down the circumstances. Although Customs and Border Protection eventually began releasing regular data on apprehensions, a lot of the debate depended on the most recent CBP data, which was from February.

As The Washington Post’s Nick Miroff reported Thursday, we can now more accurately adjudicate that debate. There was, in fact, an unusual surge in apprehensions at the border. Much of that surge involved child migrants, an exponentially more difficult group for the government to handle.

You can see the spike in apprehensions relative to the past 20 years in the graph below. The number of apprehensions was higher than at any point since early in the administration of George W. Bush.

Importantly, the type of migration also has changed since that point. Twenty years ago, many migrants were entering the country seeking seasonal employment. You can see the seasonality of the migration, which often peaked in early spring. In recent years, though, migrants often come to the United States to seek asylum, a legal claim that triggers a different process by the federal government.

The idea that the apprehensions above reflect the government tracking and arresting immigrants trying to sneak over the border is archaic. Now, many of those apprehended seek out federal authorities to proclaim their intent to seek asylum, a process that traditionally couldn’t begin until a migrant is on U.S. soil. (The Trump administration created a policy allowing asylum seekers to do so from outside the United States, hoping they would stay there. But given the nature of asylum claims — that the seekers fear for their personal safety — that policy is being contested in court.) Once detained, asylum seekers are often released from custody until a judge can hear their claims, a waiting period that can extend for years.

As noted above, children are particularly difficult for the government. A consent agreement from 1997 offers strict guidelines for how child migrants must be treated, including setting limits on the duration and type of detention they face. In a very real sense, apprehending an adult crossing the border illegally to seek work is relatively easy for the government to deal with. A child coming to seek asylum is a much trickier situation.

This first emerged in 2014, when the Obama administration was scrambling to deal with an increase in unaccompanied minors at the border, pushed north as a result of violence in Central America. The surge was relatively small, but because it was mostly children, the government’s ability to handle the increase was quickly strained. Four years later, the Trump administration experienced an increase in what the government calls “family unit aliens,” meaning at least one parent and at least one child traveling together.

Although most of the increase in March was a function of adults traveling individually, the number of unaccompanied children apprehended at the border set a record.

You can view that more easily if we break out each category of apprehension. The number of children traveling alone who were apprehended was well above the 2014 surge. The number of migrants apprehended as part of a family was lower than the peak in 2019 but well above what it has been in recent months.

Consider what that means from a functional standpoint. Those family-member numbers include parents and children but, at a minimum, mean that at least half of the total are migrants younger than 18 (because family units necessarily include a parent and one minor child). If we consider the minimum number of children apprehended at the border — both unaccompanied and traveling with a parent — the number of children taken into custody was probably higher than in any month save May 2019, the peak of the Trump-era surge.

Several things can be true. It is true, for example, that the overall surge in migration began last year, after a significant drop at the start of the coronavirus pandemic. It is also true that the number of children apprehended at the border has spiked in the past few months, when it hadn’t in 2020.

Now that we have the official data, it is also clearly true that the administration’s efforts to play down the increase don’t hold up very well.

“First of all, there was a surge in the last two years,” President Biden said in an interview with ABC News last month. “In ’19 and ’20, there was a surge as well.”

There was. The implication that what was underway at the border was therefore business as usual, though, doesn’t really hold up.