President Donald Trump on Saturday posted on social media a single sentence that appears to encapsulate his attitude as he tests the nation’s legal and constitutional boundaries in the process of upending the federal government and punishing his perceived enemies.

“He who saves his Country does not violate any Law,” Trump wrote, first on his social media platform Truth Social, then on social platform X.

By late afternoon, Trump had pinned the statement to the top of his Truth Social feed, making it clear it was not a passing thought but one he wanted people to absorb. The official White House account on X posted his message in the evening.

The quote is a variation of one sometimes attributed to Napoleon Bonaparte, although its origin is unclear.

Nonetheless, the sentiment was familiar: Trump, through his words and actions, has repeatedly suggested that surviving two assassination attempts is evidence that he has divine backing to enforce his will.

He has brought a far more aggressive attitude toward his use of power to the White House in his second term than he did at the start of his first. The powers of the presidency that he returned to were bolstered by last year’s Supreme Court ruling that he is presumptively immune from prosecution for any crimes he may commit using his official powers.

During his first weeks in office, Trump has signed numerous executive orders that pushed at the generally understood limits of presidential power, fired numerous officials and dismantled an agency in clear violation of statutory limits, and frozen spending authorized by Congress without clear authority. Many of his policy moves have been at least temporarily frozen by judges.

Such moves include trying to unilaterally rewrite the definition of birthright citizenship — a right enshrined in the Constitution’s 14th Amendment — to exclude babies born to mothers living in the country without legal permission, and mass firings of public servants, ignoring civil service protection laws. He has all but shuttered the agency responsible for foreign aid, dismissed prosecutors who investigated him, and fired Senate-confirmed watchdogs without giving proper notice to Congress or justification.

Trump’s team has embraced an expansive version of the so-called unitary executive theory, a legal ideology that says that the Constitution should be understood as forbidding Congress from placing any limits on the president’s control of the executive branch, including by creating independent agencies or restricting the president’s ability to summarily fire any government official at will.

The Trump administration at first did not offer a public legal rationale for blowing through the statutes that provide various kinds of job protections to the officials that Trump has summarily fired, including members of independent agencies like the National Labor Relations Board.

But last week, the administration offered something of an explanation. Sarah M. Harris, the acting solicitor general at the Justice Department, sent a letter to Congress saying the department would not defend the constitutionality of statutes that limit firing members of independent agencies before their terms were up. Such laws say the president cannot remove such an official at will, but only for a specific cause like misconduct.

While not using the phrase “unitary executive theory,” Harris’ letter echoed its ideological tenet that the Constitution does not allow Congress to enact a law “which prevents the president from adequately supervising principal officers in the executive branch who execute the laws on the president’s behalf” and said the Trump administration will try to get the Supreme Court to overturn a 1935 precedent to the contrary.

That, at least, is a theory under which at least some of what Trump has been doing is lawful: It is not illegal to disregard an unconstitutional statute.

But, taken at face value, Trump’s statement Saturday went much further, suggesting that even if what he is doing unambiguously breaks an otherwise valid law, that would not matter if he says his motive is to save the country.

There are a handful of instances of other presidents claiming the power to override legal limits, but those have usually been limited to national security.

In the early days of the Civil War, for example, Abraham Lincoln suspended habeas corpus rights, called up troops and otherwise spent money that Congress, which was not in session, had not appropriated.

When Congress reconvened, Lincoln sent a letter telling lawmakers what he had done and famously asking, “Are all the laws but one to go unexecuted, and the government itself go to pieces, lest that one be violated?” He also said that what he had done, “whether strictly legal or not,” had been necessary, and Congress retroactively ratified his actions.

More than a century later, after President Richard Nixon resigned to avoid being impeached in the Watergate scandal, he talked in an interview about wiretapping and other steps that might appear to be illegal but were undertaken to protect against foreign threats. Citing Lincoln’s example, Nixon said presidents have inherent power to authorize government officials to break laws if the president decides that doing so is in the national interest.

“When the president does it, that means it’s not illegal,” Nixon claimed.

And following the terrorist attacks of Sept. 11, 2001, President George W. Bush and Vice President Dick Cheney took actions that violated statutory limits on issues like torture and surveillance based on an expansive and disputed vision of the power their lawyers said the Constitution gives the president in his role as commander in chief.

While national security cases rarely get litigated, when they have, the Supreme Court has been skeptical of sweeping theories of presidential power — striking down President Harry S. Truman’s attempted seizure of steel mills as a Korean War measure, for example.

Trump’s moves so far have largely not been in the realm of national security. Rather, he has been attempting to stamp out pockets of independence that Congress created within the executive branch in order to centralize greater power in the White House over issues that are largely ones of domestic policy.

Trump and some of his allies have pushed the political argument that the nation has been under siege from what they characterize as leftist policies and values and has fallen into a spiral of decline that must be reversed by any means necessary.

Among them, Trump’s budget chief, Russell Vought, wrote an essay in 2022 declaring that the United States was already in a “post-Constitutional moment” and that to push back against liberals, it was necessary to be “radical in discarding or rethinking the legal paradigms that have confined our ability to return to the original Constitution.”

• This article originally appeared in The New York Times.