Supreme Court rulings this week supporting drug testing of some railroad and Customs workers dealt a double blow to labor's attacks on such policies, but union leaders and lawyers were split on the potential impact on dozens of broader cases.

Neither decision by the high court dealt with random drug testing, the crux of a flood of lawsuits filed by public employee unions in response to federal, state and local drug testing programs.Some union leaders found encouragement in language they said put the Supreme Court on record as supporting drug testing only in extraordinary circumstances relating to public safety.

But others said that, despite the focus of the rulings, the fact that the high court's first decisions on the issue were in favor of drug testing would lead to expanded testing programs and could influence a number of decisions pending in lower courts.

"We do not believe that these cases are controlling on the issue of random testing," said Joe Goldberg, an attorney for the American Federation of Government Employees.

Nevertheless, he said justices on lower courts with pending drug-testing cases likely would review the rulings for guidance and could also ask parties in those cases to submit their views on whether the Supreme Court rulings are relevant, ultimately delaying those decisions.

Other labor lawyers, however, were heartened by Justice Antonin Scalia's stinging dissent in the Customs case, in which he said the government had not proven in advance the need for such testing. The lawyers viewed the dissent as an indication Scalia, a conservative Reagan appointee, might frown on widespread random testing in government jobs not directly affecting public safety.

Among cases filed by AFGE are several challenges to an executive order issued by former President Reagan ordering federal agencies to adopt drug-testing programs. AFGE officials had urged a rival union involved in Tuesday's high court rulings, the National Treasury Employees Union, not to press its appeal, part of an effort to get the high court to rule first on a broader case involving random testing.

"This was a terrible case to take to the Supreme Court," said AFGE President John Sturdivant.

NTEU lost its appeal of a lower court ruling allowing the Customs Service to drug test employees seeking drug-enforcement jobs.

NTEU President Robert Tobias said there are about 9,000 Customs workers affected. During testing to date, he said 6,500 people were tested and three tested positive.

The second ruling allowed drug testing of railroad workers involved in accidents.

Lawrence Mann, the attorney for the Railway Labor Executives Association, which objected to such testing, predicted the government would attempt to use the ruling to support its position in cases involving random testing.