As legal challenges to the actions of the Trump administration mount, President Trump declared in a social media post: “He who saves his Country does not violate any Law.”

The quote was not original — it has been attributed to the French dictator Napoleon Bonaparte.

But the laws and the Constitution of the United States were crafted to prohibit Napoleon’s form of authoritarian leadership.

A key principle is that we are a government of the people with three distinct branches, each meant to serve as a check and balance to the other two.

Since its foundational ruling in Marbury v. Madison, in which the Supreme Court gave itself the power to review actions by Congress and the presidency and declare them unconstitutional when called for, the court has protected its power and that of Congress to rein in the executive branch.

In fact, the current court majority under Chief Justice John Roberts has been particularly vocal in its disdain for executive-branch agencies exerting expansive power in a way that steps on the traditional roles of the legislature and the courts.

Now, Trump seeks to expand his power even further, and in ways the current court’s majority have already rejected. He is doing this in part through a misreading of last term’s ruling granting presidents immunity from criminal prosecution for actions taken within their core constitutional duties.

Trump, through Department of Justice attorneys litigating on his behalf, argues that the immunity ruling gave him carte blanche.

Now is the time for the Supreme Court to disabuse Trump of that notion and protect its own power, and that of Congress. It’s crucial for democracy.

Just last term, the court issued a ruling freeing courts from being bound by agencies’ interpretations of the federal laws that empower them when those laws are ambiguous.

In that ruling, penned by Roberts, the court’s conservative majority held that such deference steps on the constitutional powers of Congress, which creates laws, and the courts, which interpret them.

“The very point of the traditional tools of statutory construction –the tools courts use every day — is to resolve statutory ambiguities,” Roberts wrote. “That is no less true when the ambiguity is about the scope of an agency’s own power.”

The justices should remember that as the challenges to the so-called Department of Government Efficiency, which was not created by Congress, and the authority of its de facto leader Elon Musk, who is neither elected nor Senate confirmed, land at the Supreme Court’s door.

Lawsuits, including those filed by the attorneys general of 14 states including Massachusetts and Rhode Island, are seeking to stop Musk and other DOGE agents from firing federal employees, denying funding for agencies and their programs, and other actions taken without apparent legal authority.

If the court has power to step in on cases where Congress has authorized the creation of an agency, it is clear that the court can and must step in when such an executive body is acting with no legal authority.

In response, the government essentially argues that Musk and DOGE are just extensions of Trump himself, and are protected by the broad authority the president has over actions within the executive branch.

The Justice Department even cites the Supreme Court’s immunity ruling as authority in its legal filings.

The justices must be clear that the ruling may have shielded Trump from a criminal conviction, but it does not insulate him from the limits of the Constitution. Trump cannot simply declare Musk to be his White House deputy to avoid the constitutional problem with his actions.

As the lawsuit from state officials argue, Musk is acting well beyond the authority granted to White House employees. Rather, his role is that of a “principal officer of the United States,” akin to a cabinet member. Such a position requires Senate confirmation.

That should make it easy for the justices to strike those actions down and thus restore some constitutional order.

This and other lawsuits cite violations of the Administrative Procedure Act, a law that the court has used repeatedly to strike down agency actions that do not follow the procedures laid out by Congress.

It is certainly true that the court has vastly expanded the president’s power.

But Trump has taken the inch the court has given him and is now trying to expand it to a mile. He has, literally, called himself a king. It is up to the Supreme Court, in following the Constitution, the law, and its own precedent, to let him know how wrong he is.