The candidates in the April 19 special election to fill the seat of former Senate Majority Leader Dean Skelos rolled out major endorsements Tuesday, as President Bill Clinton backed Democratic Assemb. Todd Kaminsky and 14 police unions announced for Republican Christopher McGrath.

Clinton, appearing with Nassau Democrats in Elmont for a rally to support wife Hillary Clinton’s presidential bid, cited Kaminsky’s six years as a federal prosecutor and his work passing legislation during his first term in the assembly.

“I want you to get out there and elect him,” Clinton told a crowd of several hundred people. “This is really, really important to the future of New York State. This guy, he embodies what this election is really all about.”

McGrath, an attorney from Hewlett, received the endorsement of 14 law enforcement unions at the Nassau Police Benevolent Association’s Mineola office. PBA President James Carver said it’s critical for the GOP to maintain control of the Senate to prevent New York City Democrats from diverting aid from Long Island schools.

“This is a pro-police decision ... a pro-Long Island decision,” Carver said of the unions’ endorsements.

In an interview, Kaminsky said he would “never harm our ability to get Long Island school funding.”

Kaminsky and McGrath are vying for the 9th Senate District seat, which was vacated in December when Skelos was convicted on federal corruption charges. He and his son, Adam, who also was convicted in the case, are appealing.

The race could determine the balance of power in the State Senate, which is controlled by Republicans and a group of breakaway Democrats.