The amateur video shot outside an abandoned store in Brownsville is crude. Wind blows into the microphone, the sound cuts in and out and the picture is occasionally obscured by the setting sun. None of that matters. What’s important isn’t what the camera sees, but what’s hidden from view.

A U.S. senator had tried to work through proper channels, hoping to tour a building where taxpayer dollars are being used to house an untold number of migrant children, but he explains that Homeland Security Department officials had rebuffed his request. So he flew to South Texas, personally walked up to the building and asked to speak to a supervisor. Instead of letting the senator look inside the building, the government contractor running the facility called the cops.

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“I think it’s unacceptable that a member of Congress is not being admitted to see what’s happening to children whose families are applying for asylum,” said Sen. Jeff Merkley, D-Oregon, on the Facebook Live video of the incident.

We’ve seen this movie before. The plot is pretty simple: The government doesn’t want taxpayers to see what it’s doing with children caught crossing the border illegally. The story started back in the Obama administration and it’s continuing in the Trump era, but it’s time for this secrecy surrounding juvenile detention on the border to come to an end.

The junior senator from Oregon who showed up in South Texas on Sunday has been an outspoken critic of a Trump administration policy to separate children from their parents if they cross the border without documentation — many seeking humanitarian asylum. It is a policy that has no place in a civilized society.

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A spokesman for Merkley said the senator toured a Border Patrol processing center in McAllen and saw “children in cages,” but he was denied a request to tour a Brownsville shelter for unaccompanied minors housed in a building that used to serve as a Walmart store.

We laughed when Jade Helm conspiracy theorists speculated the federal government planned to use tunnels beneath abandoned Walmart stores as detention centers for political dissidents. Now it turns out the feds are stashing children in an abandoned Walmart in Brownsville, and they won’t let a member of Congress look inside.

As much as we would all like to think those children are being treated properly, history gives good reason for suspicion. Four years ago, when an influx of undocumented immigrant children flooded into this country, federal authorities refused to reveal not only the locations of shelters, but also how many children were being detained in those facilities. U.S. Rep. Henry Cuellar, D-Laredo, got his hands on some disturbing photographs showing undocumented immigrant children kept in crowded conditions behind chain-link fences.

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It doesn’t matter what you call them — shelters, temporary housing or detention facilities — children are being held in these buildings against their will at the behest of the federal government. It doesn’t matter if they’re located on military bases or in old retail buildings, these buildings have essentially become jails. And in this country, we don’t believe in secret jails.

What the senator from Oregon did in Brownsville this week was a stunt, a piece of political theater, but it raised a legitimate point and delivered a serious message. Children separated from their parents are being detained in government financed facilities at taxpayer expense. Homeland Security officials should open all of those facilities for reasonable scrutiny. Instead of calling the cops on members of Congress and the press, they need to roll out a welcome mat.