The Miranda warning was made famous by television detectives reading the bad guys their rights and then asking whether they understood them.

After a U.S. Supreme Court decision this week, detectives - whether real or fictional - won't have to ask the follow-up question, experts say.

Previously, police had the responsibility to obtain a waiver from suspects, acknowledging that they were forgoing their rights before questioning.

The court now says police don't have to get that waiver, leaving suspects to take the initiative if they want to exercise their rights.

Basically, they have to speak up if they want to remain silent.

Veteran lawyers say Miranda rights have been eroding for years, and they were unmoved by this latest development.

"I think the practical impact will be nil," said George Parry, a Philadelphia defense lawyer who has been a federal and city prosecutor. "I've never heard of a defendant not verbally or otherwise stating that he did or didn't want to give a statement."

Nonetheless, that's what happened in the case decided, 5-4, this week, he noted.

In 2000, a Michigan shooting suspect remained silent and refused to answer questions for nearly three hours before a detective asked, "Do you pray to God to forgive you for shooting that boy down?"

The suspect said, "Yes," but he refused to sign a confession or speak further. He was convicted based largely on that one word.

"It's an interesting scenario but I doubt it's one that's occurred in more than one-tenth of one percent of the cases," Parry said.

Lt. Frank Vanore, a Philadelphia police spokesman, said that the department would consult with the District Attorney's Office on the ruling, and that no changes had been made as to how interrogations are handled.

If new training is needed for investigators and supervisors, he said, "we will ensure it's done."

David Kairys, a constitutional law professor at Temple University, said he feared the ruling could encourage detectives eager for a confession to ignore suspects' rights.

"We had this history, and we still do, of relying on confessions more than traditional proof," he said. "This will embolden whatever tendencies there already are for wrongdoing or laziness."

By putting more burden on suspects, the ruling also "makes it harder for the defendant who is improperly questioned and coerced to prove it," he said.

Christopher Warren, a Philadelphia defense lawyer, said that Miranda rights are "breached every day," but that defense lawyers can rarely prove it.

"If it comes down to what the cop says and what the defendant says, the cop usually wins," he said.

The court's latest ruling, Warren said, "is a nice little intellectual exercise, but as a practical matter, Miranda has very little teeth to begin with."

Many defense lawyers lament that interrogations are almost never videotaped, said Rocco Cipparone, a defense lawyer and former federal prosecutor in New Jersey.

If they were taped, he said, "then we're not relying on someone's perception, interpretation, or credibility . . . as to what occurred."

Miranda, originally feared to be a crippling blow to law enforcement, hasn't proved much of an obstacle. By some estimates, about 80 percent of defendants agree to answer questions.

"Regardless of Miranda warnings, if people want to give a statement, they do," Parry said. "If they don't, they don't."

Conversely, Miranda hasn't been of much help to suspects, said Dennis Cogan, a Philadelphia defense lawyer.

"The only guy who benefited from Miranda was Ernesto Miranda," he said, referring to the man whose appeal led to the namesake warning.

Contact staff writer Troy Graham at 215-854-2730 or tgraham@phillynews.com.