The Supreme Court on Monday declined to review an executive order issued by Florida Governor Rick Scott that had required all state employees take random drug tests.
The high court's decision not to hear the case means a May 2013 11th U.S. Circuit Court of Appeals ruling that found the governor's order to be too broad remains intact.
The appeals court said Scott, a Republican, could not require all employees to take tests, although it was justified for some workers, including those involved in law enforcement.
Scott defended his policy in a statement issued on Monday.
"State employees should have the right to work in a safe and drug free environment, just like in any other business," he said.
Litigation over which employees can be subject to testing will now continue in lower courts.
The 2011 executive order was aimed at all 85,000 state workers. It was challenged in court by the American Federation of State, County and Municipal Employees, which represents almost 40,000 of the workers potentially affected.
The union said the order violated the U.S. Constitution's Fourth Amendment, which prohibits unreasonable searches and seizures.
Shalini Goel Agarwal, an American Civil Liberties Union lawyer who represents the employees' union, said in a statement that the question of whether a state can require all workers to submit to a drug test without a reason has long been settled.
"Without a threat to public safety or a suspicion of drug use, people can't be required to sacrifice their constitutional rights in order to serve the people of Florida," she said.
The union did not challenge whether Scott could require drug testing of employees in safety-sensitive jobs.
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