AMNA NAWAZ: A federal appeals court offered a scathing rebuke today of the Trump administration's handling of the deportation of a Maryland resident to a mega-prison in El Salvador.

The unanimous three-judge panel called the deportation of Kilmar Abrego Garcia -- quote -- "shocking," writing -- quote -- "The government is asserting a right to stash away residents of this country in foreign prisons without the semblance of due process that is the foundation of our constitutional order."

The court also upheld a lower court's order that Trump officials can be called to testify in the case.

Maryland Democratic Senator Chris Van Hollen traveled to El Salvador to meet with government officials and push for the release of Mr. Abrego Garcia, but he was denied access to the prison.

He joins me now from El Salvador.

Senator, welcome back to the "News Hour."

Thanks for joining us.

SEN. CHRIS VAN HOLLEN (D-MD): It's good to be with you.

AMNA NAWAZ: So you went there with the intention of meeting with Mr. Abrego Garcia.

What were you told about why you would not be able to do so?

SEN. CHRIS VAN HOLLEN: Well, you're right.

I went with the intention of two issues.

One was to ask for him to release him, but the other was to see him.

And, today, I traveled to CECOT, which is the notorious prison where he's been stashed, and about three kilometers out I was stopped by soldiers, who prevented me from going any further and said they'd been ordered to not allow me to go visit with him.

AMNA NAWAZ: And have you been able to get any kind of update on Mr. Garcia's condition or whether he's had access to lawyers since he's been deported, anything like that?

SEN. CHRIS VAN HOLLEN: I have not.

And that is one of the big, big issues here, because he's not had any ability to connect with his family, with his wife, with his mom, or with his lawyers.

There's been absolutely zero communication.

I asked the American Embassy here whether they'd made inquiries on his behalf, and they said that they had not been giving any such direction from the Trump administration to inquire about his well-being.

AMNA NAWAZ: So we saw the Salvadoran president, Nayib Bukele, in the White House meeting with President Trump basically saying he's not going to return Mr. Garcia to the U.S. You said that you met with the Salvadoran vice president, Felix Ulloa, who said that their government is unable to release Mr. Garcia.

What reasons did he give you?

What did you take away from your meeting with him about why the Salvadoran government is taking this stance?

SEN. CHRIS VAN HOLLEN: Well, I told the vice president that right now El Salvador was complicit in this illegal abduction and stashing of Mr. Abrego Garcia in this prison in El Salvador, and that they should release him.

The response was what you heard from the president of El Salvador in the Oval Office, which is they can't smuggle Abrego Garcia into the United States.

And I said, well, wait a minute, we're not asking you to smuggle him back in the United States.

We're simply asking you as a sovereign country to open the gates and let him go.

After all, Attorney General Pam Bondi said at one point that they would send an airplane, but that they needed -- they, the administration, needed El Salvador to release him.

So that's why I asked the vice president simply to release him from the prison.

He's illegally detained there, and they should not be complicit in this.

AMNA NAWAZ: So I guess the real question here, Senator, is, if the Salvadorans won't release him and the U.S. government does not seem to be working to release him or bring him back, what more can be done?

What else can you do from your position?

SEN. CHRIS VAN HOLLEN: Well, I think more pressure and more of a spotlight can have an impact over time, because I think it's unsustainable for both the Trump administration to continue to thumb its nose at the U.S. courts, especially in light of the Fourth Circuit opinion upholding the district judge, and of course, the 9-0 decision by the Supreme Court.

It is unsustainable, I think, for El Salvador to say, look, we don't know anything about why we're holding him, other than the fact that the United States government is paying us up to $15 million to hold him and others.

And I think, over time, that that position will be unsustainable.

I will say, back at home, I'm certainly not going to support any taxpayer dollars going to El Salvador so that they can continue to illegally detain a resident of Maryland.

AMNA NAWAZ: As you likely know, Senator, also back here at home, after the Trump administration admitted that they had mistakenly deported Mr. Garcia, this week, they have been releasing a lot of information about the background of his case, including this message from Homeland Security.

It was titled: "The real story.

Kilmar Abrego Garcia is an MS-13 gang member with a history of violence."

They lay out details of his 2019 arrest.

They share excerpts of documents that they say prove his gang connection.

They argue at the end of that he belongs -- quote -- "behind bars and off American soil."

What's your response to that?

SEN. CHRIS VAN HOLLEN: My response to that is that the place to submit that evidence is the actual court, the federal court, not in the court of public opinion, because when they went before the federal district court judge, the judge said that they did not provide ample evidence to make their MS-13 claim.

So go into court.

That's the proper forum for bringing these claims, for bringing these charges, but they didn't do that.

Instead, they abducted him and sent him to this prison in El Salvador.

Look, I'm not vouching for any kind of particular facts.

That's up for the court to decide.

What I'm doing for - - doing is vouching for due process, which is what the Fourth Circuit just said the Trump administration is violating in such an extraordinary way, because, if we allow the Trump administration to violate due process rights in this case, you can be sure it will not be the last.

AMNA NAWAZ: Senator, you have probably also seen this week the president has floated the idea of deporting American citizens to other nations and other prisons.

He said he's looking into it.

It's something that he wants to do.

And in the court order today, this issue was addressed.

The judge wrote -- quote -- "If today the executive claims the right to deport without due process and in disregard of court orders, what assurance will there be tomorrow that it will not deport American citizens and then disclaim responsibility to bring them home?"

Do you, Senator, see a connection between this idea of deporting American citizens and this case of Kilmar Abrego Garcia?

SEN. CHRIS VAN HOLLEN: Yes, because they both have to do with people's due process rights.

And as the Fourth Circuit pointed out today, when you violate Abrego Garcia's due process rights, it's a short path to tyranny, essentially, if you allow that to happen, because next we're violating everybody else's due process, right?

So the heart of this is the fact that the Trump administration thinks that it can ignore the law, ignore judges.

They admitted in federal court that they had made a mistake in this case.

But instead of fixing the mistake, what did they do?

They fired the lawyer, they put him on administrative leave and reprimanded him for telling the truth.

So this is why this is such a danger to all of us.

And that's what the Fourth Circuit said so strongly in their opinion today.

AMNA NAWAZ: That is Maryland's Democratic Senator Chris Van Hollen joining us tonight from El Salvador.

Senator, thank you for your time.

We appreciate it.

SEN. CHRIS VAN HOLLEN: Thank you.