A federal court on Friday upheld New York’s law allowing undocumented immigrants to apply for driver’s licenses — paving the way for the measure to take effect on Saturday.

The court rejected a challenge to the law from Rensselaer County Clerk Frank Merola, who had challenged the measure’s constitutionality. It is the second time a federal court has upheld the law, which was approved by state lawmakers and signed into law in June by Gov. Andrew Cuomo.

A separate court challenge by Erie County Clerk Mickey Kearns was rejected earlier this year. Merola this week said he would direct people he believes to be in the country illegally to the motor vehicle office in Albany.

The Trump administration through the Department of Justice had signaled support for Merola’s lawsuit, writing in a filing that there were constitutional issues raised by the state law.

Dozens of county clerks who administer motor vehicle offices for the state, on Friday in a letter to the Cuomo administration, urged the law to be delayed in its implementation, pointing the lack of time for training given by the state.

“The State DMV has failed to put in place safeguards to prevent someone who has a social security number from signing the affidavit form claiming they’ve never been issued a social security number, enabling people to conceal their true identities,” the clerks said.

“In fact, State DMV representatives admitted during their conference call with County Clerks on Monday, December 9, 2019, they have no way to check or verify if a person using the affidavit form, in fact, was never issued a social security number.”

The state Department of Motor Vehicles, meanwhile, pointed to the law itself, saying the implementation is mandated by the law, adding that the law will take effect as planned.

“We invite any county clerk who feels inadequately prepared to implement the law on December 16 to contact us so we can provide further instruction or clarification,” said DMV spokeswoman Lisa Koumjian.

“The law applies to only one license transaction and the DMV is not creating a new license or overhauling the current process. We have provided document authentication devices and resource guides to both state and county DMV staff to assist them.”

Koumjian added machines used for authentication have been used across the country to verify foreign and U.S. documents and to prevent fraud.

“Moreover, long before the implementation of this new law, staff were offered hands-on training to detect fraudulent documents, and they will continue to follow the well-established process that exists today for reporting possible fraud,” Koumjian said. “The DMV’s investigative unit will also continue to utilize its tools, such as facial recognition, to prevent fraud.”

Attorney General Letitia James, whose office defended the measure in court, said in a statement that elected officials like county clerks who administer local motor vehicle offices must follow the law.

“The Green Light law is legal and enforceable, and two separate federal courts have now already dismissed the meritless claims of two county clerks,” James said.

“Beginning Monday, the law will help make our roads safer, our economy stronger, and will allow immigrants to come out of the shadows to sign up as legal drivers in our state. We expect all public officials to comply with the law, and, as the state’s attorney and chief law enforcement officer, I will continue to vigorously defend it.”

Merola in a statement on Friday afternoon vowed to fight on in the case.

“I am disappointed, and hopefully, this is only a setback,” Merola said. “We will continue to fight to be heard.”

Meanwhile, county clerks continued to criticize the state's rollout of the law. 

"The things they have set up have loosened the standards and it's troubling," said Saratoga County Clerk Craig Hayner. 

Hayner says he will follow the law at his own Motor Vehicles offices, amid concerns his staff has not been given enough guidance from state officials. 

"We are going to have to process them," Hayner said. "That is the law at this point; we'll be processing people, we're certainly very concerned, we've had the same concerns all along."

Hayner was among the dozens of counties who signed a letter urging the Cuomo administration to delay the implementation of the law. Anu Joshi of the New York Immigration Coalition cheered the measure's approval. 

"All of this taken together means for the first time in 18 years," Joshi said, "undocumented immigrants will be able to apply for a standard driver's license in New York."

Joshi says undocumented immigrants applying for licenses should not be concerned their information will be shared with federal authorities.  

"We can't guarantee everyone's safety," Joshi said. "We just can't do that. But we do know these are the strongest privacy protections of anywhere in the country and we stand by that."

Some county clerks say they won't issue licenses to people they suspect are in the country illegally, directing them to other motor vehicle offices.