At the beginning of their march, the 300 demonstrators were drenched by rain. But they laughed, shouted, raised their arms skyward and kept marching.

"This is a sign from God," said spokesman Rupert Chappelle, 30 "God designed marijuana and God cultivates and manufactures marijuana. It tastes good, it's natural and it's non-addictive. It's also good on salads and spaghetti sauce."

It was the annual "smoke-in" of the Youth International Party, better known as "Yippies." The demonstration of support for legalizing marijuana has become one of the city's Fourth of July traditions. But this year the demonstrators were on the march, barred from their usual rallying place in Lafayette Square because a coalition of counterdemonstrators had reserved the park ahead of them.

The coalition of politicians and civic groups included D.C. Del. Walter Fauntroy, several City Council members and the Concerned Citizens for Drug and Alcohol Abuse. Their demonstration, called the July 4th Family Celebration, drew about 200 persons--who were all but oblivious to the Yippies as they marched by in disarray.

"Down with Pot, Pornography and Promiscuity," Fauntroy shouted into a microphone. "Those are the three P's destroying the American family today."

"Organizers of the smoke-ins have sent fliers into our schools urging children to join in their use of marijuana," Fauntroy maintained in an interview later. "So we decided to apply for use of this park this year to make a statement against drug use."

Dana Beal, a founder of the Yippie movement, had vowed earlier in the day to "raise hell" and disturb the Family Celebration. But several demonstrators who tried to enter the park were blocked by a dozen Park Police on horseback.

A total of 20 marchers were arrested by Park Police and Metropolitan Police, officials said, 15 in narcotics-related charges and five for disorderly conduct.

"We're all here to prove pot should be legalized," said Clyde Bodge Jr., 23, who said he flew from Ontario with four others to be at the demonstration. "If we have to be arrested to prove it, we will."

But Beal acknowledged that it had been "a struggle just to have this demonstration this year. The marijuana movement is split into three groups that don't totally agree with each other. We had 5,000 people here last year."