To many, Trump’s pronouncements sounded like a direct repudiation of a long-standing conservative legal principle — that the federal government’s powers are limited to constitutionally approved subjects, like regulating interstate commerce and providing for the national defense. Many conservative legal crusades, including some enthusiastically embraced by Trump, are even based on those notions.

First, there were the Republican politicians who rebuffed Trump’s claims.

“How & when to modify physical distancing orders should & will be made by Governors,” Sen. Marco Rubio (R-Fla.) wrote Tuesday morning in a tweet that didn’t mention Trump directly but unmistakably rejected his stance. “Federal guidelines ... will be very influential. But the Constitution & common sense dictates these decisions be made at the state level.“

A key Trump loyalist in the House, Rep. Liz Cheney (R-Wyo.), threw Trump’s words back at him.

“The federal government does not have absolute power,” she wrote on Twitter, before quoting verbatim the 10th Amendment’s promise that powers not apportioned in the Constitution “are reserved to the states respectively, or to the people.”

There were also staunch proponents of executive power, like former George W. Bush Justice Department official John Yoo, who said Trump had gotten out too far over his skis.

“The federal government does not have that power. The Constitution’s grant of limited, enumerated powers to the national government does not include the right to regulate either public health or all business in the land,” Yoo, now a University of California at Berkeley law professor, wrote bluntly in National Review . “Our federal system reserves the leading role over public health to state governors. States possess the ‘police power’ to regulate virtually all activity within their borders.”

The pile-on continued on conservative blogs, with Ed Morrissey of Hot Air pleading with Trump to reverse course.

“Not just wrong on the merits, but inexplicable in the implications,” Morrissey wrote , adding that the president’s stance was both a constitutional and political error. “Regardless of what made Trump offer this argument … it’s flat-out wrong. The sooner he realizes that mistake, the better off he’ll be, unless he wants to assume responsibility for every error made by governors around the country for not having exercised this supposed authority from Day One.”

Despite the fusillade of criticism, Trump stayed true to form Tuesday and doubled down on his contention that he could control the states. He railed against New York Gov. Andrew Cuomo’s efforts to defy a White House-led reopening drive and instead form a regional alliance of northeastern governors intent on coordinating a staged return to work.

“I got it all done for him, and everyone else, and now he seems to want Independence! That won’t happen!” Trump declared .

Cuomo, a Democrat, shot back, saying that he didn’t want to fight with the president over the matter but would take him to court if there was a disagreement over when to rescind social-distancing guidelines.

“We would have a constitutional challenge between the state and the federal government, and that would go into the courts, and that would be the worst possible thing he could do at this moment,” the governor said on CNN’s “New Day."

As Trump tried to dismiss reporters’ doubts Monday about his claims, the president insisted there were “numerous provisions” of law backing up his assertions.

“We'll give you a legal brief if you want,” Trump said. No such legal justification emerged Tuesday.

That sort of advice would typically come from the White House counsel’s office or the Justice Department’s Office of Legal Counsel.

Spokespeople for those offices did not respond to requests for comment Tuesday. But Attorney General William Barr did address the issue of state and federal powers just last week, before Trump’s latest comments.

In an interview with Fox News host Laura Ingraham, Barr seemed to hew to the traditional view that most of the powers to limit activity during a pandemic reside with the states, not the federal government or, seemingly, the president.

“States have very broad — as you know, what we call police powers, very broad powers that the federal government doesn't have to regulate the lives of their citizens, as long as they don't violate the Constitution,” Barr said.

The urgency of conservatives’ retort to Trump is a signal of how central the notion of federalism and limited central government is to their legal outlook. For example, the the challenge to Obamacare’s individual mandate is based largely on the argument that the Constitution contains no language authorizing the federal government to require individuals to buy health insurance.

Claiming a general federal power to regulate local businesses, as Trump did this week, could undermine future arguments against federal efforts on the scale of the Affordable Care Act.

Still, the president has never evinced much enthusiasm for abstract ideas like federalism, even as he has vigorously placed adherents of that philosophy on the federal bench and Supreme Court. In speeches promoting his judicial nominees, Trump often praises them as brilliant, tough and the product of the finest schools, but rarely indicates any knowledge of their legal outlook.

Unsurprisingly, there is also an ebb and flow about federalism concerns in Washington that tends vary based on whichever party is in power. Some have skewered that approach as a federalism of convenience.

When Republicans are ascendant, their calls to devolve powers to the states sometimes waver. For instance, drives to crack down on same-sex marriage, assisted suicide and drug legalization all impinge on the autonomy of states but have been blessed by GOP presidents and their allies.

Similarly, Democrats — who typically hold a more robust view of federal authority — have gotten religion on states’ rights since Trump took office three years ago. They’ve gone to court dozens of times to complain about federal intrusions into issues like sanctuary city laws and state-level environmental regulations.

Many of the lawsuits attacking the Trump administration on those grounds were filed by California Attorney General Xavier Becerra. Asked a couple of years ago about whether he was comfortable adopting many of the same legal tactics that red states perfected during the Obama era, Becerra replied: “We are all federalists now.”