On Thursday, Sen. Chris Van Hollen pushed through an amendment to an appropriations measure that would force the State Department to reveal travel ban numbers it has previously kept secret. Slate spoke to Van Hollen about his amendment, the imminent Supreme Court decision on the travel ban, and his recent trip to the Mexican border to visit families that had been split by Trump’s since reversed child separation policy. The following transcript of our conversation has been edited and condensed for length and clarity.

Slate: Please describe to me your travel-ban waiver amendment in your own words.

Sen. Chris Van Hollen: The purpose of the amendment is to provide some long overdue transparency about the waiver process, because from the beginning it has appeared that the waiver process is really a sham. That it’s simply window dressing for what is really a Muslim ban, and this process has been shrouded in secrecy. We’ve tried for months to get information from the administration about this process. From start to finish, the administration has tried to hide the process they use with respect to granting waivers, and so we decided that we would require that they provide this information. The amendment requires extensive reporting every 90 days on the status of the waivers. When [the administration] first provided us information, they apparently realized just how embarrassing it was [and so they stopped providing that information]. They’ve been, as you know, just granting a trickle of waivers.

What’s the next step for the bill?

This was the last Senate Committee action. It goes from the Senate Committee to the Senate floor. Once it gets out of the Senate it will go to an Appropriations Committee conference committee, and that’s where the House and Senate will iron out the differences between the two bills. So it will be important to protect and preserve this provision, so it’s in the final bill that goes to the White House to the president.

Your amendment doesn’t seem particularly controversial at this point, because it passed with broad bipartisan support?

We worked very hard to have this included in the managers’ package, which is just a term for a package of amendments that is presented to the committee by both the chairman and the ranking member. Because we were successful in getting [this amendment] in that package—I’m confident that we will get this through the Senate.

“They’re trying to hide this information because they know if it comes to light it will expose the program as a sham.” — Sen. Chris Van Hollen

In a recent court attestation, a former consular officer described the waiver process as a sham. According to my reporting, Solicitor General Noel Francisco also appears to have given the Supreme Court inaccurate and misleading information about this process. If Francisco gave the court bad information, do you think he should correct the record?

I certainly believe that if the solicitor provided the court with misinformation—again, if the solicitor provided the court with misinformation—then the solicitor has a duty to report the accurate facts to the court. If the solicitor made a misstatement before the court [about the waiver process], it’s also of course a misstatement in the letter that we received [from the State Department]. This is why it’s important that we get to the bottom of this. This is why we’re demanding transparency. We can’t figure out the percentage of people who get a waiver without knowing the overall number of people who apply for a waiver. Our impression is that they’re trying to hide this information because they know if it comes to light it will expose the program as a sham.

There appear to be countless stories of elderly people, sick people, young children—people who in no plausible way are a national security threat to the United States of America—who have been denied waivers. Justice Ruth Bader Ginsburg during oral arguments in Trump v. Hawaii brought up the case of the 10-year-old girl with cerebral palsy who was initially denied a waiver. What do you think when you read these stories?

When you see waivers being denied to kids with cerebral palsy or to very elderly individuals who are coming to the United States because they’ve lost a loved one, it tells me that this policy is being applied more as a blanket exclusion with very few exceptions and—again—that the overall intent of the way they’re implementing this program is to exclude people who do meet the criteria [for a waiver]. Otherwise they wouldn’t be taking the discretion away from consular officers, [as is apparently the case].

I want to ask you about family separation. As a member of the U.S. Senate, what are you going to do to ensure that the families that have already been separated are reunified, and to ensure that the policy of indefinite separation is not re-implemented if the president’s executive order on Wednesday fails in the courts?

“This reversal has its own set of really big problems.” — Sen. Chris Van Hollen

We’re going to pursue every means possible to have families that have been separated reunited, and we will continue to sort of demand that the president reunite these families. I’ve already begun talking to our colleagues about legislative vehicles [to reunite families]. Obviously those have to take a longer and windier road to pass, and they always run the risk of getting caught up in the larger immigration debates. But one thing that became clear from [the administration’s] despicable and inhumane family separation policy was the power of public opinion. So we need to bring that power to bear on the issue of reuniting parents with their kids. It was just sickening to see what was happening at the border when I went down there [during a recent trip] and to see the brutality of this Trump policy in action. We spoke to moms who had been separated from their kids. They were understandably in tears. It was a very emotional moment. It was a moment where everyone said what the hell is this country doing—meaning, really, what the hell is President Trump doing? This was one of those moments where the country did rally together to demand a reversal. Obviously this reversal has its own set of really big problems. [The president’s executive action] doesn’t have anything about reuniting families. The second issue, which is just unacceptable, will be the indefinite detention of children. That is absolutely unacceptable. We’re going to be working on both those fronts going forward.

Did you hear that audio of children crying in a detention center and the Customs and Border Patrol agent apparently mocking them? Also, have you had the opportunity to meet children who have been separated from their parents?

Van Hollen: I heard that really awful tape, and it made me cry for our country. It made me ask, what is happening here? How could we have a government policy that results in little kids separated from their parents and left in tears. That tape and the pictures and the stories coming out of the border are what drove public opinion very quickly to demand this change.

They would not let us talk to any of the kids when we were at the border. We were allowed to talk to the moms in two places. But we were prevented from talking to the kids. They said that was a matter of policy and protecting the kids. I find it very ironic that […] the [administration that] put kids in detention are now claiming that they’re protecting them from us. The first place we went [is] called the “Ursula” [Border Patrol] Processing Center in McAllen, Texas, locally known as the “dog kennel.” That’s where you walk in and see these pens of kids who have been separated from their parents behind chain link fences. The parents are kept in another pen. It was one of those other moments where you just ask yourself: How did we come this? How does a president of the United States issue an order that leads to such cruelty towards children and others?

Did you actually cry tears when you listened to that audio and have you cried at all at other points during this whole thing?

I definitely got very choked up when we were talking to the mothers at the Port Isabel Detention Center. That was probably the toughest moment.

Are you going to challenge the efforts to prevent you and your Senate colleagues from meeting the children? [Editor’s note: After this interview, it was reported that the administration is going to allow members of Congress to visit some of the separated children.]

We are looking into whether that’s a current rule or regulation, or that was just the ad hoc decision of the administration. You can imagine there being rules in place to prevent strangers from talking to kids, and we can all understand that. But I think it’s also hard to argue that the purpose behind any such rules is to prevent kids from having a discussion with members of Congress who are there to expose an inhumane policy.

You would think that the parents—if they had any say—would want the members of the U.S. government who cared to do so, to bring attention to the plight of their children.

Absolutely. On a separate related issue, I can tell you a Kafkaesque situation we encountered. This wasn’t a child separation [case], but it does have to do with immigration detention [policy]. We were trying to help one person who’d been detained. In order for a congressional office to help them, you need to get a personal privacy waiver from the person. It was a woman who had come from the Philippines in the late 1990s. She had three children; one of them—her son—is an Iraq War veteran. She was detained [by immigration officials], [the family] reached out to us; [the Department of Homeland Security] said in order for us to help them, she had to sign a privacy waiver. So her son—an Iraq war veteran—went to the detention center to get her to sign it and they wouldn’t let him in. So, they made it impossible for her to sign a privacy waiver, which they demanded that we sign before we could help her. It was outrageous. I [also] included an amendment in one of the bills we just passed in the Senate Appropriations Committee to require that [immigration officials] provide people detained with these privacy waivers, so that we can help them.