In its immunity decision Monday, the Supreme Court emphasized the long-cherished ideal that no one in America is above the law, not even the president.

The court’s dissenters and a chorus of critics said the majority had undercut that notion, elevating the president to a king who can easily avoid prosecution. They warned of future presidents unbound from the rule of law who could freely engage in criminal activity. And they pointed to the prospect of a second term for Donald Trump — the man whose indictment on charges related to his efforts to overturn the 2020 election prompted the Supreme Court to weigh in — as a moment when their worst fears could be realized.

“If a future president sitting in the Oval Office were to want to commit crimes, up to and including subverting an election or remaining in power against the will of the American people, this opinion, in my mind, could provide a road map for that,” said David Becker, the executive director of the Center for Election Innovation and Research.

Becker, a former voting rights attorney with the Justice Department, said he believed the prosecution of Trump for his past behavior can advance in some form. But holding Trump and other presidents accountable will be far more difficult after Monday’s ruling, he said.

Like the court’s dissenters, led by Justice Sonia Sotomayor, Becker cited hypothetical examples of presidents ordering the military to kill their political rivals.

“If the secretary of defense does it, and whether it’s successful or not, everyone involved in that crime could be prosecuted save for one person — the person who ordered it,” Becker said.

Before Trump, no current or former U.S. president had ever been charged with a crime, though some have come close. Richard M. Nixon was forced to resign for his involvement in the Watergate scandal and later received a pardon from his successor, Gerald Ford.

Former Nixon White House counsel John Dean said Monday that had the court’s ruling been in force in the early 1970s, history could have turned out very differently.

“As I looked at it, I realized Richard Nixon would have had a pass” because the evidence against him was based on official acts the Supreme Court has deemed immune from prosecution, Dean told reporters.

The Watergate scandal began with a break-in at the headquarters of the Democratic National Committee and expanded to include a host of clandestine and illicit activities in which the Nixon administration and campaign played a part, resulting in dozens of convictions of Nixon aides and associates.

Dean, who became a star witness during the Watergate investigation, called Monday’s ruling “a radical decision by a radical court” and “judicial activism on steroids.”

The decision arose from the Trump legal team’s contention that he enjoys broad immunity that should spare him from special prosecutor Jack Smith’s indictment of the former president on charges that include a conspiracy to defraud the United States.

The Supreme Court ruled presidents have absolute immunity for actions they take as part of their primary responsibilities and are presumed immune for other official acts, but are not immune from charges related to unofficial acts. The ruling dealt a blow to prosecutors, who now will have to persuade a trial judge to allow the case to continue.

University of Notre Dame law professor Derek Muller said the decision makes it harder to prosecute presidents but does not give them a pass.

“It definitely gives more protection to the president, but I think there are pitfalls for future administrations if they were to rely too heavily upon it,” Muller said.

The lines between official and unofficial acts can be blurry, as they are in Trump’s case, Muller said. The decision leaves open the possibility that Smith’s charges against Trump over the election can continue, and it provides some protections to President Biden if he loses to Trump this fall, Muller said.

“It prevents President Trump from prosecuting former president Biden, if that’s the case, on a great many things,” he said. “So there is a way in which it will de-escalate rhetoric about a president or a candidate threatening to prosecute a former president for official acts.”

He called the hypothetical example of an assassination plot absurd. To start, others would likely be loath to carry it out because they would fear they could be prosecuted, he said.

Much more has to play out in the Trump case in the lower courts, and the case could easily return to the Supreme Court, he said. In short, the precise details of when presidents enjoy immunity remain unclear.

“I don’t know that I would be citing this too readily if I’m president trying to evade criminal responsibility in the future,” Muller said.

The decision was written by Chief Justice John G. Roberts Jr. and joined in full by four other Republican nominees to the court. The other Republican nominee, Justice Amy Coney Barrett, joined most of the decision but dissented from part of it.

The three Democratic nominees dissented in an opinion by Sotomayor that contended the majority had created a “law-free zone around the President.”

“Orders the Navy’s Seal Team 6 to assassinate a political rival? Immune,” she wrote. “Organizes a military coup to hold onto power? Immune. Takes a bribe in exchange for a pardon? Immune. Immune, immune, immune.”

The majority’s ruling, she said, meant that presidents no longer face the same consequences everyone else does. “In every use of official power, the President is now a king above the law,” she wrote.

She ended her opinion by writing, “With fear for our democracy, I dissent.”

Roberts in his majority opinion said the dissenters had gone too far in saying the president is above the law. Accounting for the president’s sweeping powers, Roberts wrote, “does not place him above the law; it preserves the basic structure of the Constitution from which that law derives.”

The dissenters, Roberts wrote, were engaging in “fear mongering on the basis of extreme hypotheticals.”

In an all-caps post on social media, Trump praised the ruling as a “BRILLIANTLY WRITTEN AND WISE” decision that would causes charges against him to disappear or “WITHER INTO OBSCURITY.”

The former president is running even or better than Biden in most polls with four months to go until the election. Trump was convicted by a New York jury in May for behavior that preceded his presidency and remains charged in three other cases.

Critics held up the dissent as an all-too-real preview of what could come in America if a future president feels he can behave with impunity.

“When dissenting justices warn that the majority may have just legalized murder by one individual in our country, that warning is to be taken very seriously,” said Norm Eisen, a senior fellow at the Brookings Institution who served as special counsel to the House Judiciary Committee for Trump’s first impeachment.

The decision, Eisen said, “opens a dangerous tear in the American constitutional fabric and the checks and balances that have helped us to survive as a country for two-and-a-half centuries.”

Biden campaign co-chairman Cedric L. Richmond said the ruling was a reminder to voters to reject Trump at the polls.

“Trump’s court has left our country vulnerable to an attack from within,” Richmond said in a written statement. “It has removed the guardrails that protect us from a president trying to be a dictator.”

Trump was acquitted during two impeachments, and it’s difficult to imagine the Senate convicting any president in an impeachment because of the country’s intense political polarization, said Becker, the director of the election research center. With the legal system now constrained by Monday’s ruling, Becker said, the main means of holding a president to account now comes down to the public.

“There’s one primary check on preventing corrupt, unscrupulous individuals from abusing the executive branch,” he said. “And that is the vote.”