Washington CNN  — 

Now we know what Justice Ruth Bader Ginsburg was doing while recuperating from cancer surgery and fielding calls about the Oscar-nominated documentary based on her life story.

She was delving deeply into the history of the excessive fines clause of the Constitution.

On Wednesday, her second day back on the bench, she read – in her usual steady voice – an opinion holding that the Eighth Amendment’s ban on excessive fines applies to states and local governments, as well as to the federal government.

In her opinion, she traipsed through history: the Magna Carta, the 17th-century Stuart kings, the Virginia Declaration of Rights and the 14th Amendment.

“For good reason, the protection against excessive fines has been a constant shield throughout Anglo-American history: Exorbitant tolls undermine other constitutional liberties,” she wrote.

The ruling was a win for an Indiana man who pleaded guilty to dealing drugs and committing fraud but argued that police were wrong to seize his $42,000 Land Rover. He said the seizure was grossly disproportionate to the gravity of his offense.

“The biggest implications of today’s ruling are likely to be felt in civil forfeiture cases, in which state and local governments will now have to confront an important additional limit on the value of property that they can seize that is not directly part of a criminal sentence,” said Steve Vladeck, a CNN Supreme Court analyst and University of Texas School of Law professor.

“Given that the same limits already apply to the federal government, and the widespread concerns over the proliferation of civil forfeiture in certain states, it’s not especially surprising that the justices ruled this way – or that they were unanimous in doing so,” Vladeck added.

It was Ginsburg’s first opinion issued since she’d had cancer surgery in December following the oral arguments in the case in late November, which she was present for.

“In short, the historical and logical case for concluding that the Fourteenth Amendment incorporates the Excessive Fines Clause is overwhelming,” Ginsburg wrote. “Protection against excessive punitive economic sanctions secured by the Clause is, to repeat, both fundamental to our scheme of ordered liberty and deeply rooted in this Nation’s history and tradition,” she said.

After reading the opinion, Ginsburg launched into oral arguments in a patent case. She was unusually active in her questioning.