Merrick Garland, the US attorney general, was denied a lifetime seat on the Supreme Court by Republicans in the Senate.

He now faces a decision arguably every bit as weighty as anything he may have faced on the nation's highest court: the potential prosecution of a former president of the United States.

The 69-year-old Garland personally approved the stunning August 8 FBI search of Donald Trump's Florida home and will have the final say on whether he is to be charged with any crimes.

Such a move against a former president would be unprecedented -- Richard Nixon was pardoned by Gerald Ford before any criminal charges could be brought stemming from the Watergate scandal.

And while Nixon was a spent force anyway -- having resigned in disgrace -- the 76-year-old Trump retains an iron grip over the Republican Party and is openly mulling another run for the White House in 2024.

"The idea of prosecuting a former president for anything is pretty extraordinary," said Steven Schwinn, a law professor at the University of Illinois Chicago. "But Trump's actions were pretty extraordinary."

While the Mar-a-Lago raid appears to center around the mishandling of classified documents, Trump is also facing legal scrutiny for trying to overturn the results of the November 2020 election and for the January 6, 2021, attack on the US Capitol by his supporters.

Trump has not been charged so far in connection with either case but the House committee probing the Capitol riot, in a series of public hearings, has laid out a roadmap for Garland to potentially follow.

Whether he will do so is the burning question in the nation's capital.

The raid on Trump's Florida home ignited a political firestorm and indicting him would ratchet up tensions even further in a country already bitterly divided along Democratic and Republican lines.

Garland is politically astute enough to foresee the consequences of going after Trump, Schwinn said, and has "complicated considerations to put in the balance."

"On the one hand, Garland has got to be thinking about what his job is -- and that is enforcing the rule of law," he said.

"On the other hand, he is undoubtedly aware that any criminal pursuit of President Trump is going to embolden his base and has already led to threats of violence against federal officers and others."

'Without fear or favor'

Trump and his Republican allies have already accused Garland, who was named the country's top law enforcement official by Democratic President Joe Biden, of "weaponizing" the Justice Department for political purposes.

"Nothing like this has ever happened to a President of the United States before," Trump said after the raid on Mar-a-Lago, calling it a "witch hunt" by vengeful Democrats.

The FBI raid prompted Trump ally Marjorie Taylor Greene to introduce a resolution in the House to impeach Garland for a "blatant attempt to persecute a political opponent."

It has no chance of passage in the Democratic-controlled chamber.

On the left, some Democrats have accused Garland of moving too slowly in taking legal action against a former president they believe should be behind bars for mounting an insurrection.

A graduate of Harvard Law School, the professorial and soft-spoken Garland is no stranger to high-profile investigations.

As a federal prosecutor, he notably led the probe into the 1995 Oklahoma City bombing by far-right extremists that left 168 people dead. He also prosecuted Ted Kaczynski, the "Unabomber."

Garland went on to serve as chief judge on the US Court of Appeals for the District of Columbia and was nominated to the Supreme Court by president Barack Obama in March 2016.

But the Republican majority in the Senate declined to hold a vote on his nomination and it was the next president -- Donald Trump -- who ended up filling the vacant seat.

A stickler for protocol, Garland has tried to adhere to the Justice Department's policy of not commenting on ongoing investigations.

He was forced to abandon his usual reticence amid the furor sparked by the FBI raid and briefly addressed reporters last week, citing what he called the "substantial public interest in this matter."

He said the decision to search Trump's home was not taken "lightly" and stressed that "the rule of law means applying the law evenly without fear or favor."