NEW YORK — Powered by a solid triumph in California, Hillary Clinton declared victory in her yearlong battle for the heart of the Democratic party, seizing her place in history and setting out on the difficult task of fusing a fractured party to confront Donald Trump.

Clinton cruised to easy victories in four of the six state contests on Tuesday — including delegate-rich New Jersey. With each win she further solidified Sen. Bernie Sanders’ defeat and dashed his already slim chances of using the last night of state contests to refuel his flagging bid.

The much-needed winning streak allowed Clinton to celebrate her long-sought “milestone” — the first woman poised to lead a major political party’s presidential ticket. Standing before a flag-waving crowd in Brooklyn, the former secretary of state soaked up the cheers and beamed.

“Barriers can come down. Justice and equality can win,” she said. “This campaign is about making sure there are no ceilings, no limits on any of us. This is our moment to come together.”

Clinton had already secured the delegates needed for the nomination before Tuesday’s contests, according to an Associated Press tally. Still, Sanders had hoped to use a victory in California to persuade party insiders to switch their allegiances. Sanders picked up wins in Montana and North Dakota. But Clinton’s substantial lead in California made it clear his effort was faltering.