A U.S. Supreme Court decision Thursday in a Massachusetts cocaine trafficking case is expected to have wide-ranging ramifications in drug prosecutions and create an even longer backlog in court and at the state drug testing lab.

The high court ruled in a 5-4 decision that crime lab reports used in drug and other cases can be introduced as evidence at trial only if defendants can cross-examine the forensic analysts who prepared the reports.

Prosecutors use drug certification reports in thousands of cases each year and, until the high court ruling Thursday, were not required by state law to present "live" witnesses at trial, lawyers on both sides said.

But in a 2002 cocaine trafficking case out of Suffolk County, the high court ruled a defendant's constitutional right to confront witnesses against them extended to reports of forensic analysis.

The decision was praised by defense lawyers who said it upheld a person's Sixth Amendment right to confront witnesses and guaranteed a fair trial for the accused. But it has arisen concerns among prosecutors about bogging down already overburdened chemists at the state drug lab, where there is already a six- to nine-month wait for drug certifications, and clogging up courts.

"I think everybody should be happy about this. It renews your faith in the Constitution and upholds the rule of law. The Sixth Amendment guarantees your right to confront witnesses against you," said Joshua Werner, a South Easton defense lawyer and former Suffolk County prosecutor.

Werner received notice about the decision on his Blackberry while in Taunton District Court, where he represented a drug defendant who ultimately admitted police caught him with drugs.

"It's a landmark decision," said North Attleboro defense lawyer Brian Roman said, adding it will require the prosecution to substantiate its evidence, especially in drug cases where quantity is an issue.

On the other hand, Roman wondered what short-term solution the state will come up with to deal with the requirements of the decision.

"They will have to revamp the whole drug certification process. They are going to have to testify in courts on a regular basis," Roman said of state drug analysts.

David Frank, a reporter for Lawyers Weekly and a former Bristol County prosecutor, agreed.

"It's a logistical nightmare, with all the drug cases there are every day in courts throughout ht the state," said Frank, who has been following the case.

About 20 states already give defendants some right to cross-examine lab employees about forensic evidence.

The case decided by the high court involved a Massachusetts man convicted of trafficking in cocaine, partly on the basis of a crime lab analysis that certified that cocaine was in plastic bags found in a car in which he was riding. The judge at his trial rejected objections from defense lawyers who argued the analyst who prepared the report must be called to testify about the testing method, how the evidence had been preserved and other issues.

Massachusetts and other states, along with the U.S. Justice Department, had argued before the Supreme Court that requiring lab workers to testify would be costly and time consuming, resulting in long delays and backlogs in court and in crime laboratories.

Massachusetts Attorney General Martha Coakley, who argued the case before the high court, issued a statement saying she was "very disappointed" by the ruling.

"The majority in this 5-4 decision rejected the reasoning of the Massachusetts Appeals Court and Supreme Judicial Court that permitted routine drug test results to be admitted at trial without requiring live testimony from the laboratory analysts," she said.

"It is particularly disappointing that the majority failed to appreciate that its ruling today will significantly burden our ability to prosecute countless drug cases in the commonwealth's courts," Coakley said.

The attorney general said her office is still reviewing the implications of the decision and is prepared to work with other law enforcement officials in the state "to adjust our practices to comply with this new constitutional rule while still holding accountable those who violate our drug laws."

Writing the court's majority opinion, Justice Antonin Scalia said the constitutional right of defendants to confront witnesses against them cannot be relaxed simply because it makes the prosecution's task more burdensome.

He said the practice in many states already followed the ruling, and the serious disruption predicted by the state and by court's dissenting justices has not occurred.

Chief Justice John Roberts and Justices Anthony Kennedy, Stephen Breyer and Samuel Alito dissented.

"The court sweeps away an accepted rule governing the admission of scientific evidence. Until today, scientific analysis could be introduced into evidence without testimony from the analyst who produced it. This rule has been established for at least 90 years," Kennedy wrote.