Andrew M. Cuomo was resoundingly elected to a third term as governor of New York on Tuesday, riding Democratic enthusiasm in a deep blue state to beat back his Republican challenger and capture a victory for the party’s old guard.

In defeating Marcus J. Molinaro, the Dutchess County executive, Mr. Cuomo, 60, soaked up the vast majority of votes in New York City, mirroring his success in the September primary, in which he defeated Cynthia Nixon, the actress and education advocate. The race was called by The Associated Press shortly after polls had closed at 9 p.m.