Some of President Trump’s top aides on Monday misstated several key facts involving the deportation of a Maryland man to El Salvador last month, blatantly contradicting other members of the administration who have maintained for weeks that his expulsion was an “administrative error.”

In remarks from the Oval Office and on television, Mr. Trump’s advisers suddenly declared that the man, Kilmar Armando Abrego Garcia, had been lawfully sent to a prison in El Salvador.

The White House also sought to portray a recent Supreme Court ruling in Mr. Abrego Garcia’s case as a victory when in fact the decision was a nuanced one. It partly found in favor of Mr. Abrego Garcia while also leaving open a loophole for the administration to avoid bringing him back from El Salvador.

The efforts by the Trump administration to misrepresent the case came as President Nayib Bukele of El Salvador announced after a meeting with Mr. Trump that his government would not return Mr. Abrego Garcia to U.S. soil.

Here are some of the ways in which the White House has twisted the facts.

A top Trump adviser said Mr. Abrego Garcia had not been mistakenly deported.

When Mr. Abrego Garcia, a Salvadoran immigrant, was arrested while looking for work at a Home Depot in Maryland in 2019, a judge determined that he should not be deported to his homeland because he might face danger there. The ruling, known as a “withholding from removal” order, meant that he could stay in the United States with a measure of legal protection.

In March, however, he was suddenly pulled over by federal agents who accused him of being a member of the Salvadoran gang MS-13 and inaccurately told him that his protected status in the country had changed. Within three days, he was on a plane with other migrants to a prison in El Salvador called CECOT, which is known for its human rights violations.

After Mr. Abrego Garcia’s family sued the government seeking his return, several Trump administration officials — including the United States solicitor general — made a rare admission: The White House had made a mistake when it deported Mr. Abrego Garcia.

But on Monday, Stephen Miller, Mr. Trump’s top domestic policy adviser, abruptly changed course. He declared on Fox News that Mr. Abrego Garcia had not in fact been wrongfully deported.

“He was not mistakenly sent to El Salvador,” Mr. Miller said, adding, “This was the right person sent to the right place.”

The sudden turnabout was remarkable not only because Mr. Miller, who is not a lawyer, contradicted previous assertions by some within the administration, but also because he appeared to go against the findings of the Supreme Court. In their recent ruling in Mr. Abrego Garcia’s case, the justices immediately stated that the government itself had taken the position that “the removal to El Salvador was the result of an ‘administrative error.’”

That view had already been advanced in court papers by a top official at U.S. Immigration and Customs Enforcement and by D. John Sauer, Mr. Trump’s newly appointed solicitor general. It was also offered during a court hearing this month by Erez Reuveni, a Justice Department lawyer who was handling the case — that is, until he was fired this weekend, according to a person familiar with the matter.

Mr. Miller blamed a Justice Department lawyer for admitting the deportation was wrong.

In one of the more remarkable moments in his appearance on Fox News, Mr. Miller blamed Mr. Reuveni — and only Mr. Reuveni — for having planted the idea that Mr. Abrego Garcia’s deportation had been in error.

“A D.O.J. lawyer who has since been relieved of duty, a saboteur, a Democrat, put into a filing, incorrectly, that this was a mistaken removal,” Mr. Miller said.

That assertion, however, flew in the face of the fact that other Trump officials had said the exact same thing.

One of them was Mr. Sauer, a top-ranking Justice Department official. Another was Robert Cerna, the acting field office director for enforcement and removal operations at ICE.

Early in the case, Mr. Cerna submitted a sworn declaration about Mr. Abrego Garcia’s deportation, and made clear that it was a mistake.

“This removal was an error,” he said.

Moreover, just a few weeks before he was fired, Mr. Reuveni was praised as a “top-notched” prosecutor by his superiors in an email announcing a recent promotion.

The attorney general did not fully explain what the courts have said about Mr. Abrego Garcia and MS-13.

Mr. Trump and his top aides have repeatedly accused Mr. Abrego Garcia of being a member of MS-13. They have also said at times that he is a terrorist — but only because the administration recently designated MS-13 as a terrorist organization.

In the Oval Office on Monday, Attorney General Pam Bondi said that two courts — an immigration court and an appellate court — had “ruled” that Mr. Abrego Garcia was a member of MS-13. But Ms. Bondi’s statement was a bit misleading.

To be clear, Mr. Abrego Garcia has never been charged with — let alone convicted of — being a member of the gang. But during his deportation proceedings, some evidence was introduced that he belonged to MS-13, and judges decided it was enough to keep him in custody while the matter was resolved.

But other judges have found the same evidence to be lacking.

When Judge Paula Xinis, who has been overseeing the efforts to bring Mr. Abrego Garcia back to the United States, considered the accusations that he was a gang member, she decided they were less than persuasive.

“The ‘evidence’ against Abrego Garcia consisted of nothing more than his Chicago Bulls hat and hoodie, and a vague, uncorroborated allegation from a confidential informant claiming he belonged to MS-13’s ‘Western’ clique in New York — a place he has never lived,” Judge Xinis wrote in an order last week.

In its daily update to Judge Xinis outlining what steps it has taken to return Mr. Abrego Garcia to the United States, the Justice Department, submitting its filing more than an hour late, echoed many of the recalcitrant remarks that administration officials made in the Oval Office. It included the assertion that in 2019, a judge had determined that Mr. Abrego Garcia was a member of MS-13.

Mr. Miller portrayed the Supreme Court’s ruling as a clear victory for the administration.

When the Supreme Court handed down its ruling in Mr. Abrego Garcia’s case last week, its findings were complicated and rather ambiguous.

The justices endorsed Judge Xinis’s previous order that required the administration to “facilitate” the return of Mr. Abrego Garcia. But they stopped short of actually ordering his return, indicating that even federal courts may not have the authority to require the executive branch to do so.

And yet Mr. Miller, in his appearance on Fox News and in the Oval Office, portrayed the ruling as an unmitigated victory for the Trump administration.

He said, for instance, that the Supreme Court’s instructions that the White House had to “facilitate” getting Mr. Abrego Garcia out of custody meant that Trump officials could assume an entirely passive stance toward his release.

“If El Salvador voluntarily sends him back,” Mr. Miller said on Fox News, “we wouldn’t block him at the airport.”

But whether that position flies with Judge Xinis remains to be seen. She has scheduled a hearing to discuss what the government should do for Tuesday in Federal District Court in Maryland.

Mr. Miller also seized upon a small portion of the justices’ ruling that directed Judge Xinis to take the first crack at telling the White House what to do. The justices cautioned Judge Xinis that as she considered that issue, her ultimate decision needed to be made “with due regard for the deference owed to the executive branch in the conduct of foreign affairs.”

The Justice Department used that line in a court filing on Sunday to suggest that the courts were powerless to dictate how the White House should act because the president alone has broad powers to handle foreign policy.

“The federal courts have no authority to direct the executive branch to conduct foreign relations in a particular way, or engage with a foreign sovereign in a given manner,” lawyers for the department wrote. “That is the ‘exclusive power of the president as the sole organ of the federal government in the field of international relations.’”

Glenn Thrush contributed reporting.