Thirteen-year-old Jessamyn Franks disapproved, but she would have given him a second chance.

Former Supreme Court nominee Douglas H. Ginsburg, who admitted last week that he had smoked marijuana, "should not have a past like that," Franks said as she marched yesterday in a Lions Club-sponsored "Say No to Drugs" demonstration in Fairfax County.

"But if he's big enough to admit he made a mistake, he should not have to go through the guilt," said the eighth grader from Luther Jackson Intermediate School.

While Ginsburg's imperiled nomination dominated the morning news yesterday, about 150 students walked from Seven Corners to Mason District Park "to make people more aware of the drug problem and to show there is some support from students" for avoiding drugs, said marcher Beverly Hoffman, 16.

Like Franks, most of the marching teen-agers disapproved of what they called Ginsburg's "mistake."

"It's disappointing," said Kandy Cameron, 15, a few hours before the 41-year-old appeals court judge withdrew his nomination because of the disclosure. But he should not be disqualified, Cameron added, "as long as he's not taking drugs now and it doesn't affect his job now."

Some dismissed Ginsburg's experience with the drug as a widespread folly of "his generation."

"I think it's the kind of thing most people have gone through in that age group," said Ayesha Hussain, 16, of Arlington. "I think he's being unjustly criticized."

"I guess in his generation . . . they weren't as aware of the consequences {of drugs} as we are now, and it was more of a peer pressure thing to do," Cameron said.

March coordinator and Lions member Daniel Stabile said he was disappointed by the low turnout for the march -- he had planned on more than a thousand participants -- but he called it a "small step forward" and one the service organization hopes to run annually.

Antonio McKay, 23, Olympic gold medalist for the 400-meter race and the 4-by-4-mile relay, came from his home town of Atlanta to lead the march. "Any time I can contribute to people saying no to drugs, I try to be there," he said.

The athlete, as well as Rep. Frank R. Wolf (R-Va.), walked with the students and later praised them for their position against drugs as they snacked on soda and Twinkies in the park.

Among the marchers were about 25 students from Harpers Ferry Junior High School in West Virginia, the first school to host a visit from First Lady Nancy Reagan on her national "Say No to Drugs" campaign, according to teacher Linda Hine.

Hine said the school's antidrug club, which started about a year ago, has about 65 members. Although drug abuse is not a major problem in the rural town, Hine said, the club was organized as "preventive drug therapy."

Her students did not mention Ginsburg's marijuana smoking as they prepared to travel by bus yesterday to Fairfax County, Hine said.

"But the adults did," she said. "I was hit with this when I went to buy sandwiches this morning." When she walked into a Harpers Ferry cafe to make the purchase, the clerk's "first comment to me was, 'I'm really concerned for Mrs. Reagan. {President Reagan} should have checked this out better.' "