Accused cocaine king on trial, but drugs still flow. The cocaine smuggling trial of Carlos Lehder Rivas comes at a low-point of antidrug cooperation between the US and Colombia.

Federal agents see the trial of accused cocaine kingpin Carlos Lehder Rivas - which began this week in Jacksonville, Fla. - as the most important in the history of the war on drugs. Mr. Lehder's trial follows a major bust last week in Miami of what the FBI calls the most sophisticated drug transportation ring they have ever uncovered. The FBI says the 30 Americans arrested were a kind of high-tech drug courier service.

But neither development, federal agents say, can be expected to make even a brief dip in the still-growing tide of cocaine into the US.

Cocaine, according to the US Drug Enforcement Administration (DEA), is the only major drug whose usage has continued to increase. While amounts of cocaine seized by federal agents have nearly doubled in the past two years, estimates of cocaine consumption, which includes crack, have grown, too. And the price has dropped over the past few years, indicating that supply is plentiful.

According to DEA estimates, as much as 80 percent of the cocaine consumed in the US passes through the hands of the Medell'in cartel, a loose confederation of cocaine organizations named after the mountain resort in Colombia that many of the leaders call home.

Lehder, according to US investigators, was a founding leader of the cartel and the most brash and reckless of them. He was captured by Colombian police last February and extradited within hours on a US government plane to Florida.

That smooth extradition has since proved to be a peak in the cooperation of the US and Colombia against the drug lords.

The capture followed massive anticorruption purges of the state and local police forces in the Medell'in area. Colombia had a new president, and popular outrage against the cocaine tycoons was running high after a respected antidrug newspaper editor was murdered.

Since then, Colombia's supreme court has voided its extradition treaty with the US over what American officials see as a technicality. To US Rep. Charles Rangel, chairman of the House Select Committee on Narcotics, this move shows that Colombia has become a ``narcocracy, not a democracy'' - a country ruled by drug lords through fear and intimidation. Thousands of murders in Colombia this year alone are attributed to drug traffickers.

Joint effort between the US and Colombia, says Mr. Rangel, ``has come to a standstill.'' Elliott Brown, minority staff director of the committee, calls the cocaine trade ``an international force, unprecedented in the annals of history, capable of bringing governments to their knees.''

The voiding of the treaty is a victory for Lehder, even as he sits as a defendant in a US federal court on 11 cocaine trafficking, conspiracy, and racketeering charges.

For years, his fiercest battles have been against Colombia's extradition treaty with the US. Using the rhetoric of Colombian nationalism, Latin racial pride, and anti-Americanism - mixed with some Hitlerian anti-Semitism - Lehder even founded a political party to quash the treaty.

Because it is now voided, Lehder and other alleged top officers of the cartel are protected from facing separate federal charges in Miami indicting him as a member of the Medell'in cartel as a criminal organization.

Federal drug agents say they have been making progress against the Medell'in cartel. The American smuggling ring broken last week in Miami stands accused - like Lehder - of trans porting cocaine for the Medell'in cartel. The FBI also recouped millions of dollars of drug money headed back to South America in a national money laundering sting operation, ending about six months ago.

But drugs flow unimpeded. Altogether, says DEA spokesman Jack Hook in Miami, major arrests have had ``no impact on the amount of cocaine that the Medell'in cartel is manufacturing and importing into the US.''

The cartel, he adds, ``is run like a major corporation.'' It has contingency plans and backup systems for delivering its product to its largest customer, the US. The cartel is also, he says, ``the most vicious, the most violent organized-crime group that has ever hit the US. We just won't rest until we shut them down.''

The Lehder trial is expected to last more than three months.

Prosecutors portray Lehder as one of the four biggest cocaine dealers in the world, driven by an insatiable greed and hatred of the United States.

But defense lawyers criticize the prosecution, saying the government had promised special treatment to criminals in exchange for their testimony against Lehder. ``Your government is literally buying Lehder's conviction,'' Miami attorney Edward Shohat said yesterday in opening arguments.

If convicted of the charges, which concern the smuggling of 3.3 tons of cocaine into Florida and Georgia between 1978 and 1980, Lehder faces a maximum sentence of life in prison.