The number of drug cases in federal courts has jumped more than 300 percent since 1980, transforming the federal courts in some parts of the country into little more than processing plants for low-level drug offenders, according to figures from the Administrative Office of the Courts and interviews with judges.

In the District of Columbia, southern Florida, Texas, California and the Southwest, courts are being forced to abdicate their traditional role as forums for important constitutional issues in order to deal with the drug case influx, judges say.

One stark example came here last week, when lawyers representing federal employees went to court with a First Amendment challenge to a law barring all federal employees from accepting outside income from speaking engagements or writing.

The lawyers asked the judge to stop the law from going into effect on Jan. 1, but U.S. District Judge Thomas Penfield Jackson denied that request on narrow procedural grounds. The plaintiffs then asked for another hearing, hoping to argue the merits of the case more fully and change Jackson's mind before being forced to appeal.

Jackson bluntly told them to forget getting a hearing date any time soon. "I have seven drug trials scheduled for January," he said. "I wish you Godspeed to the fifth floor" -- the D.C. Circuit Court of Appeals.

Increasingly, judges say, courts are having to push those kinds of cases, as well as important federal contract disputes or administrative law issues, to the back burner to accommodate criminal drug cases.

"Until a few years ago, I really did spend about 50 percent of my time on civil cases," said U.S. District Judge Judith N. Keep of San Diego. Now, she said, "our courtrooms on Mondays, when we do sentencings, are generally filled with poor Mexican families who are just trying to comprehend what in the world has happened to their relatives."

The transformation is the product of a collision of events over the last decade: more drug-related crime, a war on drugs that has increased the number of federal prosecutors, mandatory penalties that give defendants no incentive to plead guilty, and sentencing guidelines that make even entering a guilty plea a time-consuming mini-trial.

And it is producing a shock wave of unintended results, say judges and other legal experts, including a demoralized federal judiciary and a backlog in civil cases that is denying ordinary citizens access to the federal courts.

"It's gotten to the point where we're very close to not having a civil court," said J. Lawrence King, the chief federal district judge in Miami. "The ordinary citizen then has no place to go if his spouse has contracted asbestosis working in a Navy shipyard and is dying . . . {or where they} can decide whether or not there can be a Christ child at City Hall at Christmastime. . . . Where do those people go?"

For some first offenders, the transformation also produces severe sentencing disparities. Thanks to federal mandatory sentencing laws, a first offender caught carrying 50 grams of crack now faces 10 years in prison without parole in federal court -- at least seven years more than he might serve under state law in Florida, Texas, New York, California or the District.

State courts have also been overwhelmed with drug cases in the past decade, when cocaine swept the country and crack became a widespread addiction. But the war on drugs has become an all-consuming occupation in federal courts for several reasons.

One is the federal Speedy Trial Act, which requires that all criminal cases go to trial within 70 days of indictment. Unlike most state court cases, criminal cases in federal courts automatically move to the front of the calendar.

Because federal courts do not have jurisdiction over a host of ordinary state crimes such as burglary and assault, the percentage of drug cases in federal courts tends to be higher. And because mandatory minimum sentences give defendants no incentive to plea bargain, more cases than ever are going to trial.

"We're trying more cases than we used to," said Judge Francis J. Boyle, chief federal judge in Rhode Island. "You get more defendants who want to just take a shot at it and hope the jury makes a mistake."

Many drug cases take up an inordinate amount of time because they have multiple defendants. Chief Judge Gordon Thompson Jr. of San Diego has his own rule of thumb: "You can try about nine at a time." When there are more than that, he divides it into more than one trial.

Many defendants do not speak English. A large Panamanian drug case recently prosecuted here involved wiretapped conversations in Spanish played aloud for the benefit of the defendants. Every 10 minutes or so, the tape halted while a translator read the same conversation in English, for the benefit of the jury. As the tortuous process continued, weeks of trial stretched into months.

In some places, especially the District, prosecutors and drug task forces are steering cases out of local courts into federal courts to take advantage of the tougher federal penalties, say judges and prosecutors. Traditionally, federal drug cases were complex prosecutions of large narcotics rings. Now, judges say, they are processing scores of small-time offenders, all of whom face heavy prison terms.

"They are almost always the bottom of the distribution machine," said Judge Keep, whose district sits on the Mexican-U.S. border. "Many of them are basically very decent people driven by tremendous poverty. They'll be offered a couple of thousand dollars to drive a vehicle five blocks across the border. That money . . . will take care of the family for a couple of years in Tijuana."

The increase in drug cases has not hit all federal courts equally. Figures compiled by the Administrative Office of the Courts show that the effect has been most pronounced in 14 federal districts -- most in the Southwest, where narcotics accounted for more than 40 percent of the criminal cases filed last year.

But the District had the highest percentage of all: nearly 64 percent, because U.S. Attorney Jay B. Stephens has steered a number of street-sale drug cases out of D.C. Superior Court into federal court.

Increasingly, judges in the courts most affected say they are burning out.

"I sound like a broken record when I get on the bench," U.S. Magistrate Patrick Attridge said, referring to the opening spiel he recites for the dozens of drug defendants who appear each week in his court. Other judges here say they no longer have time to think about any other complex legal questions, such as national security issues, that also find their way into federal court in the nation's capital.

"Suits against the government, involving the State Department or the Navy -- all that has to be set aside," said U.S. District Judge Harold H. Greene. "If you want to do any writing or research on difficult issues, you have to do those on evenings and weekends."

In San Diego, U.S. District Judge J. Lawrence Irving quit in October, citing the stress from handling scores of drug cases and the lack of discretion he had in sentencing. In Miami, King said, Judge Thomas E. Scott in his district recently quit for similar reasons. "He was burned out and worn out with all the drug cases," King said.

Even the ambiance of federal court is changing. In the District, the marble hallways of the federal courthouse once echoed with the footsteps of corporate lawyers from high-priced firms litigating an antitrust case or a federal contract dispute.

Now they often look more like the hallways of D.C. Superior Court: harried defense lawyers huddle with their clients, police officers smoke and swap stories while waiting to testify, worried mothers juggle crying babies.

Throughout the country, judges say they are watching such changes with increasing concern -- both for their own well-being and that of the people who come into their courts.

"I seriously worry about the kind of persons we're going to be releasing {from prison} in years to come," said Judge Keep, citing all those Mexican families crowding into her courtroom on sentencing days. "We have really got to consider this. We are sinking into a mire of drug cases."