Davis rejected that argument, finding that one of the rapes and one of the assaults counted as violent felonies, and along with a drug conviction, that qualified him for the longer sentence.

Rosenstein said that procedure made sense, giving judges the ability to consider the facts of old cases as his office does when deciding whether to bring charges. "We know for a fact that a lot of these second-degree assault pleas are very serious and violent crimes."

But the Supreme Court said that approach by judges is unreliable.

"The meaning of those documents will often be uncertain," Justice Elena Kagan wrote for the majority. "And the statements of fact in them may be downright wrong."

Instead, Kagan wrote, sentencing judges should only consider whether the barest elements of the crime — those that prosecutors must prove beyond a reasonable doubt — make the offense necessarily violent. According to the high court, California's burglary law did not qualify.

Neither did Maryland's second-degree assault statute, which covers everything from unwanted touching to a violent beating, the 4th U.S. Circuit Court of Appeals ruled later.

In the aftermath of that ruling, at least one inmate convicted in Maryland, Ronald Hamby, has already been released. Despite some violence in his past, his case stands in contrast to that of Crockett.

He was convicted on a federal gun charge in 2007 and, because he had three prior second-degree assaults on his record, received a 15-year sentence.

Judge William D. Quarles Jr. said at Hamby's sentencing that he regretted the term he had to impose. He added, "Mr. Hamby, sentencing is never a pleasure for a judge, and there are some things that make it considerably less pleasant, such as sending a 26-year-old person away for 15 years."

Attorney Joseph L. Evans, who defended Hamby at trial, said in a recent interview that his client was not the kind of person the law was intended to target.

Evans said the assaults "weren't stranger-on-stranger incidents. It wasn't like some sort of gang activity, or drug-related activity. It was youngish guys acting out in stupid ways that violated the law."

After the Supreme Court ruling, Hamby challenged his 15-year sentence and was resentenced to the time he had already served in prison plus two weeks. He was released from federal custody in February.

Patel said the federal public defender's office is seeking to revise sentences in gun cases as well as others in which defendants were marked as career offenders.

While all the cases in dispute differ, Rosenstein said his office faces a difficult time upholding the long prison terms it originally secured.

He called new interpretations of sentencing laws "one-way ratchets in favor of the defendants." Had prosecutors known the sentences were vulnerable, Rosenstein said, they might have used a different strategy — pursuing a different combination of charges, for example — to obtain a similar outcome.

Mary Price, general counsel of the advocacy group Families Against Mandatory Minimums, said that is one of the benefits of the Supreme Court ruling.

Rather than letting prosecutors depend on the mandatory sentences, the new approach will require them to work a bit harder to convince judges to hand out long prison terms, keeping the bench as a check on the system, she said.

"Mandatory minimums provide prosecutors control over what the sentence is," Price said. "That whole setup has a problem with it."

And though Quarles expressed uneasiness in Hamby's case, Davis said he would have imposed a long sentence even if Crockett had not qualified for the 15-year minimum.

Ultimately, Patel said, despite Rosenstein's warnings, the legal challenges to lengthy sentences will not undermine the whole system. The 68 inmates who are mounting challenges represent a fraction of the 1,500 or so he said have received the enhanced sentences in Maryland.

"The statutes haven't changed, the courts were interpreting them wrong," he said. "The sky's not going to fall."