Metro

Wins battle to succeed Morgy as DA

Boosted by an endorsement from the legendary Robert Morgenthau, Cyrus Vance Jr. coasted to victory last night in the Democratic primary for Manhattan district attorney — marking the first time in 35 years that the borough’s voters have chosen a new top prosecutor.

Vance grabbed 44 percent of the vote, Leslie Crocker Snyder had 30 percent and Richard Aborn scored 26 percent, with all precincts reporting.

The victory hands the keys to 1 Hogan Place to Vance, since there is no Republican challenger in November.

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“I am so proud to have won this primary, and I am looking forward to serving you,” Vance said at his victory party last night.

Morgenthau, who stood beaming next to Vance, said the election “confirms my confidence in the wisdom of the voters of this city.”

Vance, 55, will be just the third person elected to the storied office in 68 years. Morgenthau, 90, was first elected in 1974 and his predecessor, Frank Hogan, began his three-decade stint in 1941.

The victory puts Vance — who grew up in the shadow of his famous father, former US Secretary of State Cyrus Vance Sr. — in charge of almost 500 lawyers and catapults him to the helm of the high-profile office.

The mad dash for the top slot began in earnest in February when Morgenthau announced he was stepping down.

Within weeks, word leaked out that he was bypassing his second-in-command, Daniel Castleman — who had toiled under him for 30 years in the hopes of eventually taking the reins — to endorse Vance. That decision prompted one source in the DA’s office to label Morgenthau a “Judas” for not endorsing Castleman, who quit in a huff.

With that inauspicious beginning, Vance’s campaign lurched forward.

Early polls gave the edge to Snyder, who in the 1990s made a name for herself as a no-nonsense judge. She hammered into Vance for his decision to leave New York to live in Seattle for 16 years.

In addition, Aborn — a virtually unheard-of political newbie — had a surprisingly strong start, scoring key endorsements from a spate of elected officials and the powerful, union-backed Working Families Party. Aborn has said he will not run on the WFP ticket and will support the Democratic nominee.

Ultimately, Vance won the top job, thanks to help from Morgenthau — who took to the streets to campaign for his pick — and endorsements from every major newspaper in the city, including The Post.

jennifer.fermino@nypost.com