Many New Yorkers approve of the way she has handled the transition from a decade of Mr. Cuomo’s iron-fisted reign and appear inclined to give her more time to acclimate to the job — while some Democrats would prefer Ms. James to stay as attorney general to see through existing cases, including one involving Mr. Trump and his business dealings.
Ms. Hochul and Ms. James are unlikely to be the only contenders for the nomination, and there is a real possibility of the kind of messy, crowded primary that some party leaders, wary of Democratic infighting, had hoped to avoid.
Two of Ms. James’s fellow Brooklynites, Mayor Bill de Blasio and Jumaane D. Williams, the public advocate, are both taking steps toward campaigns for governor and could cut into her coalition in New York City.
Representative Thomas Suozzi, who represents Long Island and a sliver of Queens, has also been considering a run. Unlike the other possible contenders, he would seek to outflank Ms. Hochul as a moderate option in the race as she works to build strength in Nassau and Suffolk Counties. Steven Bellone, the Suffolk County executive, is also weighing a campaign.
But for months, the question of whether Ms. James would run was the defining issue of the nascent primary contest, with some allies describing her as deliberative, and others growing increasingly eager to learn her decision as other aspects of the race came into focus.
Her answer goes a long way toward cementing the contours of the field.
Now, perhaps the biggest unknown is the question of how Mr. Cuomo may seek to involve himself in the race. The former governor, who as of the most recent filings continued to maintain a large war chest, and his team have repeatedly sought to question Ms. James’s integrity, attacking her in emails and letters sent to onetime supporters.
“The fact that the attorney general — as predicted — is about to announce a run for governor is lost on no one,” Richard Azzopardi, a spokesman for Mr. Cuomo, said in response to the complaint on Thursday.
