While the Justice Department argues in court that it is working to comply with judges’ orders to provide migrants with due process before deporting them, President Trump and his top advisers are increasingly making a different argument altogether: Why should we?

In their rapid, maximalist campaign to apprehend and deport as many migrants as possible as quickly as possible, Mr. Trump and top members of his administration have abandoned any pretense of being bound by the constitutional limits that have constrained presidents of both parties in the past on immigration. Instead, they are asserting that when it comes to people who entered the United States illegally, the president has unchecked power to expel them without recourse, and that he has neither the time nor the obligation to do otherwise.

“We’re getting them out, and a judge can’t say, ‘No, you have to have a trial,’” Mr. Trump said on Tuesday in the Oval Office. “The trial is going to take two years. We’re going to have a very dangerous country if we’re not allowed to do what we’re entitled to do.”

He made similar remarks on social media on Monday, writing: “We cannot give everyone a trial, because to do so would take, without exaggeration, 200 years.”

Such statements are alarming to legal experts who note that in the United States civil rights are for everyone — not just citizens.

“It’s enormously disturbing,” said Erwin Chemerinsky, the dean of the law school at the University of California, Berkeley. “It is so troubling to hear the president and top executive officials give so little regard to the Constitution. It’s important to emphasize that the due process clause of the Fifth Amendment says no person can be ‘deprived of life, liberty or property, without due process of law.’ It doesn’t say ‘citizen.’”

In recent days, Mr. Trump and his top advisers have railed against judges who have blocked their quick deportation efforts; declared there should be no trials for those accused of violating immigration laws; and mocked calls for those arrested to receive due process.

“I find it incredible that there’s all this push for more and more and more due process, more process for these designated terror groups, when, in fact, no one asked for due process when they crossed the border,” Thomas D. Homan, Mr. Trump’s “border czar,” said Wednesday. “No one asked for a vetting when they crossed the border. Where was all the media?”

The Supreme Court has held that immigrants present in the United States, regardless of legal status, are guaranteed due process rights, but what qualifies as due process varies depending on the person’s legal status and circumstances. Congress has created an expedited process for removing undocumented migrants who are newly arrived to the country, with limited opportunities for judicial review.

But the Trump administration is trying to go beyond that process by invoking wartime powers that erode fundamental principles of American society, said Lee Gelernt, a lawyer for the American Civil Liberties Union who is the lead counsel in the challenges to the administration’s use of the law, the Alien Enemies Act.

“The right to due process is not a luxury, but one of our nation’s foundational principles, separating us from authoritarian regimes where someone can be picked up off the streets and never heard from again,” he said.

Mr. Chemerinsky said due process was particularly important because law enforcement often makes mistakes.

Some of the men the Trump administration deported had been identified as gang members based on their tattoos or certain articles of clothing, including a basketball jersey featuring the Chicago Bulls or the team’s former star Michael Jordan.

“Governments make mistakes, and due process is a way of making sure that if somebody’s going to be deported, they’re being deported lawfully,” he said.

Entering his second term, Mr. Trump pledged to carry out rapid deportations. While some of those arrested can be legally deported quickly without a hearing under immigration law — because they had been caught at the border, had resided in the country less than two years, or had already been under a deportation order — many must go through a formal process, which includes a hearing before an immigration judge. And immigration cases nationwide face a huge backlog.

In an attempt to get around the normal process, Mr. Trump invoked the Alien Enemies Act as a way to deport immigrants he accused of being members of Tren de Aragua, a violent Venezuelan street gang the administration said had invaded the United States. The law, which passed in 1798, had been used only three times before in U.S. history, all during periods of declared war.

Stephen Miller, the White House deputy chief of staff for policy and homeland security adviser, wrote on social media this month: “Friendly reminder: If you illegally invaded our country the only ‘process’ you are entitled to is deportation.”

Mr. Trump has even suggested he might send American citizens to serve sentences abroad. “Homegrowns are next,” he told El Salvador’s president, Nayib Bukele, who is holding Venezuelan migrants in a notorious prison, during a recent White House visit.

But at every turn, the Trump administration has found lawyers and judges standing in its way.

At one hearing, before the U.S. Court of Appeals for the District of Columbia Circuit, Judge Patricia Millett pointed out that the last time the Alien Enemies Act was invoked, against suspected Nazis during World War II, those accused were provided a 30-day notice to contest the accusation, and a hearing.

“Nazis got better treatment under the Alien Enemies Act than what has happened here,” Judge Millett said last month.

Early on Saturday, the Supreme Court temporarily blocked the administration from deporting a group of Venezuelan migrants it accused of being gang members under the expansive powers of the rarely invoked wartime law.

The Supreme Court has also ruled that those subject to the statute needed to be given the opportunity to challenge their removal.

“I hope we get cooperation from the courts, because we have thousands of people that are ready to go out, and you can’t have a trial for all of these people,” Mr. Trump said Tuesday. “It wasn’t meant. The system wasn’t meant. And we don’t think there’s anything that says that.”

The Trump administration has also been dogged by the case of a Salvadoran immigrant living in Maryland who was deported to El Salvador because of an “administrative error.” The Supreme Court instructed the administration nearly two weeks ago to “facilitate” his return so he could go through the legal system in the United States, but the White House has so far not fulfilled that order.

The White House posted on social media that the man, Kilmar Armando Abrego Garcia, was “never coming back.”