A federal judge in Miami Wednesday cast serious doubts about Gov. Rick Scott’s order requiring thousands of state government employees to undergo a random drug test, suggesting his policy “sweeps too broadly.”

U.S. District Judge Ursula Ungaro peppered a government lawyer with questions about the constitutionality of Scott’s policy, saying she had “trouble understanding the circumstances under which the executive order would be valid.”

Jesse Panuccio, deputy general counsel for Scott’s office, did not provide specific examples but rather talked generally about the harm of drug use among state employees in the workplace. “Drugs are very harmful,” he told the judge. “They’re very dangerous.”

Ungaro said she would soon make up her mind about the legal challenge to Scott’s policy by the American Civil Liberties Union of Florida. The group argues that his order violates the Fourth Amendment rights of state workers because the testing requirement is “suspicionless” and therefore an illegal search and seizure.

“For the consent [to the search] to be valid, it has to be voluntary,” ACLU lawyer Shalini Goel Agarwal argued. “This blanket drug testing is unconstitutional.”

The legal challenge to the governor’s order, which has been placed on hold by Scott himself until the dispute is resolved, centers on whether the state has a constitutional right to require random drug tests of existing public workers and mandatory testing of all new employees. The governor issued his order last March.

Meanwhile, the Legislature is considering a proposed law that would mandate random drug tests of state employees every three months.

As it stands, Scott’s order affects a pool of 80,000 state employees who work for agencies under the governor, but does not extend to agencies overseen jointly by the governor and Cabinet, such as the departments of Revenue and Education or the Public Service Commission.

Scott has defended the order as a policy the public wants, and a protection the state should have.

“Look, the private sector does this all the time,” Scott said last June, when he suspended his order on drug testing while the federal court in Miami hears the ACLU challenge.

“Our taxpayers expect our state employees to be productive, and this is exactly what the private sector does,” he said.

But the ACLU, which is representing the American Federation of State, County and Municipal Employees, the nation’s largest union for state workers, counters that random drug testing was ruled unconstitutional in a 2004 case against the Florida Department of Juvenile Justice.

Random drug testing is not allowed, a federal judge ruled in that case, except for those jobs that affect public safety and in instances where a reasonable suspicion of abuse exists.

Federal courts in Florida and other states have cited the Fourth Amendment right against unreasonable searches, concluding that governments cannot require job applicants to take drug tests absent a “special need,” such as safety.

In October, a federal judge in Orlando echoed that legal view when she temporarily blocked Florida’s controversial law requiring welfare applicants be drug tested to qualify for benefits.

Miami Herald staff writer Toluse Olorunnipa contributed to this story.