WASHINGTON — The U.S. Supreme Court on Monday rejected Florida Gov. Rick Scott's petition to review a ruling that his random drug testing policy for state employees is unconstitutional, the latest in a series of legal battles facing the governor.

The decision leaves in place a May 2013 appeals court ruling against Scott's 2011 executive order making consent to suspicionless drug testing a condition of employment. A judge had previously concluded that the program, covering up to 85,000 state workers, violated Fourth Amendment rights against unreasonable searches.

The 11th U.S. Circuit Court of Appeals did grant Scott some leeway, saying drug testing without suspicion could be used in "certain safety-sensitive categories of employees — for instance, employees who operate or pilot large vehicles, or law enforcement officers who carry firearms in the course of duty."

Lawyers are still arguing about which employees could be subjected to random tests. It could take months to sort out.

Scott pressed an appeal on the broader policy to the Supreme Court in January, ignoring a warning from U.S. District Judge Ursula Ungaro — who first ruled against the program in April 2012 — that there was "probably about zero" chance of success.

Scott, a Republican seeking re-election in November, avoided any acknowledgement of a setback in a statement Monday. He largely suspended the policy when the lawsuit arose in 2011.

"State employees should have the right to work in a safe and drug-free environment, just like in any other business," he said. "The merits of this case are still being deliberated in the U.S. Southern District Court, and we will continue to fight to make sure all state employees, who are paid by taxpayer funds, can work in a safe, drug free workplace."

"What part of 'no' does he not understand?" said Howard Simon, executive director of the American Civil Liberties Union of Florida.

The ACLU and a labor union criticized Scott's appeal to the U.S. Supreme Court as a waste of taxpayer money.

"We are pleased that the Supreme Court has agreed with what we have known all along: the question of whether the state has the power to compel all employees to submit to suspicionless searches without a good reason is settled and the answer is 'no,' " said Shalini Goel Agarwal, lead ACLU counsel in the case. "Every court that has heard Gov. Scott's argument agrees: without a threat to public safety or suspicion of drug use, people can't be required to sacrifice their constitutional rights in order to serve the people of Florida."

The state's largest public employee union, the American Federation of State, County and Municipal Employees, said Scott's executive order, one of his first actions after winning the 2010 election, put a "needless cloud of suspicion" over workers.

"Today's decision by the court lifts that cloud once and for all and says that people don't lose their constitutional rights simply because they work for the public," said AFSCME Florida Council 79 president Jeanette D. Wynn.

Scott faced similar defeat Dec. 31, 2013, when a federal judge struck down a law requiring Florida cash welfare recipients to pass a drug test. It could constitute an illegal search and seizure, a judge said.

The state is appealing.

"Our hand in that case is strengthened by today," Simon said on Monday. Simon pointed to a January 2013 ACLU report that it was involved in nine lawsuits challenging policies of Scott or the GOP-controlled Legislature, ranging from drug testing to election law changes and a 2011 law banning doctors from asking patients about guns.

"We've had to reorganize our staff, add lawyers, in order to defend the rights of Floridians largely against their own government," Simon said.

The ACLU has sought public records about the legal costs of defending drug testing. The Tampa Bay Times/Miami Herald has also asked for that information, which was not available Monday. The costs are expected to be in the hundreds of thousands of dollars.

Times/Herald staff writer Steve Bousquet contributed to this report. Contact Alex Leary at leary@tampabay.com. Follow him on Twitter @learyreports.