Speaking to reporters on Tuesday, President Biden acknowledged that the Centers for Disease Control and Prevention’s nationwide eviction moratorium, which expired on July 31, had violated the Constitution. Then he announced that the CDC would revive that unlawful moratorium and extend it until October. That was a political victory for left-wing Democrats who had been urging Biden to unilaterally extend the moratorium, regardless of the legal objections. It was also a defeat for the rule of law and a glaring violation of the president’s oath to “preserve, protect, and defend the Constitution.”

Biden conceded that the eviction ban, first instituted last September under Donald Trump, had failed the separation-of-powers smell test and been repeatedly rejected by federal judges. “Look, the courts made it clear that the existing moratorium was not constitutional,” the president said. The Supreme Court ruled in June that the eviction ban could not be extended past its July 31 expiration date; the controlling opinion by Justice Brett Kavanaugh stressed that it would take “clear and specific congressional authorization” — an actual law, not a mere CDC regulation — to extend it. Biden knew all this; he had said for days that he had no authority to unilaterally maintain the moratorium. He underscored the point on Tuesday: “The bulk of the constitutional scholarship says that it’s not likely to pass constitutional muster,” he told reporters.

Whereupon, caving to pressure from his party’s progressive wing, he went ahead and did it anyway.

It was an egregious breach of the president’s duty, spelled out in Article II, Section 3 of the Constitution, to “take Care that the Laws be faithfully executed.” The eviction moratorium has proved unwise, unfair, and counterproductive, but even if it were a brilliant solution to a national problem, it would not justify Biden’s lawlessness.

Alas, he is not the first president to brazenly act in defiance of the law. If he assumes he can get away with it, perhaps that is because he learned as much from his predecessors.

In 2019, for example, Trump refused to abide by Congress’s decision not to appropriate funds for the construction of a new border wall. After lawmakers passed a spending bill without the money he wanted, Trump declared that the US-Mexico border was in a state of emergency, and that he was therefore permitted to divert billions of dollars appropriated for other purposes to build a wall. Congress resisted, voting to overturn Trump’s emergency declaration. But it couldn’t override his veto, and the unlawful power grab stood.

When Barack Obama was in the White House, he repeatedly rebuffed requests to unilaterally impose a moratorium on deporting so-called Dreamers — immigrants brought unlawfully to the United States as children — or their families. Again and again he explained that he was bound to enforce laws passed by Congress. “I’m not a king,” he told one interviewer. “I’m required to follow the law.” Then, in 2014, came a 180-degree reversal. Obama issued the executive order he had long said would be unlawful. The explanation from the White House was that “there are some things that have changed,” but the Constitution wasn’t one of them.

Before Obama decided he could disregard legal provisions he didn’t wish to enforce, George W. Bush had done the same. In scores of “signing statements” issued as he put his signature to bills passed by Congress, Bush contended that he could disregard provisions in the new measures that he deemed unconstitutional constraints on his power. But presidents have no such power. They can veto legislation they find objectionable, but bills they sign become law in their entirety. “By signing a particular bill into law and then issuing a signing statement that declares that he will not give effect to it,” wrote Brookings Institution scholars Norman Ornstein and Thomas Mann, “the president effectively circumvents these constitutional requirements, as well as displaces the courts as the final expositor of the Constitution.”

There was a time when presidents were far more scrupulous about upholding the rule of law. Inconceivable as it may seem today, when presidential overreach is rationalized on grounds of nothing ventured, nothing gained, presidents in an earlier age were prepared to block even measures to which they were personally sympathetic when they thought the Constitution stood in the way.

Once such president was James Madison, the renowned “Father of the Constitution.” In 1817, near the end of his second term as president, Madison vetoed a highly popular bill providing federal funds for building roads, canals, and waterways — what today would be called an infrastructure bill. Madison was all for internal improvements, but he vetoed the bill because, as he read the Constitution, nothing authorized the federal government to pay for the construction of state infrastructure.

Madison’s successor, James Monroe, held himself to the same standard. When Congress in 1822 passed a bill to repair the Cumberland Road, the first major highway linking the East with the growing Western settlements in Ohio and Indiana, Monroe felt constrained to veto it as an unconstitutional encroachment on state affairs. “It is with deep regret, approving, as I do, the policy, that I am compelled to object,” he wrote. “Congress does not possess the power, under the Constitution, to pass such a law.”

Few politicians today regard any problem as being outside the purview of Congress, but political leaders in earlier generations thought differently. In 1854, President Franklin Pierce vetoed an appropriation of funds to assist the mentally ill. He knew only too well how debilitating mental illness could be — his wife Jane suffered from deep depression — but he felt bound not to let personal compassion override the rule of law. “I cannot find any authority in the Constitution for making the Federal Government the great almoner of public charity throughout the United States,” his veto message explained. “To do so would, in my judgment, be contrary to the letter and spirit of the Constitution.”

It may seem naive in 2021 to suggest that the letter and spirit of the Constitution should still carry more weight in presidential decision-making than political or even humanitarian considerations. But before they enter the White House, presidents swear, hand on the Bible, to do precisely that. If we no longer expect them to keep their word, maybe it’s time to scrap the presidential oath.

(Jeff Jacoby is a columnist for The Boston Globe).