WASHINGTON — New York has thrown up some towering figures in recent years: a once-invincible presidential candidate, a billionaire mayor considered White House material, and a hard-charging governor who pledged to clean up Albany.

Now Senator Clinton’s campaign is struggling, Mayor Bloomberg isn’t running, and Governor Spitzer resigned amid a prostitution investigation.

Into this political power vacuum — which has stalled a number of massive development projects in New York City that seemed within reach after 9/11 — has stepped Senator Schumer, who is increasingly telling New York how to get back on track.

In doing so, the two-term Democrat is assuming an unusually direct role in local matters for a senator.

“It’s an engagement with internal state politics that most senators shy away from out of self-interest,” a dean at the State University of New York in New Paltz, Gerald Benjamin, said. “Typically, their posture is, ‘I’ll serve the state in Washington, I’ll work with you locals and your job is to leave me alone.'”

The senator freely admits he is trying to “give them a push” on development issues, though he rejected the suggestion of a power vacuum in the Empire State.

“It’s harder and harder to build big projects, and yet that’s always been part of New York’s greatness,” he said. “New York used to be known for grand public works, but in the last 15 or 20 years it has sort of come to a standstill.”

Mr. Schumer has long been outspoken on development issues, but his voice carries much further these days, now that others have grown quiet.

Mr. Bloomberg is a lame duck, with about a year and a half left in office. Many of his major goals, from congestion pricing tolls to a West Side stadium for the NFL’s New York Jets, died prematurely at the negotiating table in Albany.

Mr. Spitzer, who had pledged to get economic development plans moving again, stepped down after just 14 months in office without leaving much of a mark. Governor Paterson is still getting a grip on state government and has yet to assume a strong leadership role.

The other big name in New York politics — New York’s junior senator — has spent 17 months traveling the country in a bid for the White House that now appears headed for an unsuccessful ending.

Besides the absence of powerful politicians, a number of key aides who oversaw development also have departed.

“The whole upper administrative structure and the agencies are in a state of flux,” a professor of politics at Baruch College, Doug Muzzio, said.

“There is turmoil and there hasn’t been much movement. And if you look at what the Bloomberg administration has done in terms of its physical legacy, there isn’t much.”

Enter Mr. Schumer, who was raised in Brooklyn and began his political career in the state Assembly before becoming a congressman and then, in 1998, a senator.

Frustrated by a long line of setbacks in a plan to move the railroad under Pennsylvania Station into the majestic post office building across Eighth Avenue, Mr. Schumer said the Port Authority should take over the project, diminishing the role of the city. If the agency pushed the much-delayed project to completion, it would be a significant political victory for Mr. Schumer.

Mr. Bloomberg called the senator’s suggestion a terrible idea, and essentially told Mr. Schumer to butt out. “We set the city’s priorities, they don’t come out of Washington,” the mayor told reporters last week.

Mr. Schumer, for his part, then blasted Mr. Bloomberg’s plan to redevelop a forlorn stretch of commuter rail yards near the Hudson River into a commercial and residential center featuring a tree-lined pedestrian boulevard, which he dubbed “the goofiest thing I’ve ever seen.”

More typically, the job of a state’s congressional delegation is to wrest money for the folks back home. In that capacity, Mr. Schumer helped win over $130 million from Congress for the proposed new Amtrak station and played a critical role in obtaining a $20 billion federal aid package after the attacks of Septmber 11, 2001.

Neither the Democratic Mr. Spitzer, Governor Pataki, the Republican who preceded him, gave that much consideration to Mr. Schumer, though the new governor has been more supportive.

Mr. Schumer has his work cut out for him. His call to get busy building comes as the industry is coping with fewer financing options, due in large part to the credit crunch that has gripped Wall Street following the collapse of the housing market.

In an interview last week, the senator pointed to his long involvement not just in New York City projects, but in the mega-shopping mall near Syracuse called Destiny, the Peace Bridge in Buffalo, and Renaissance Square in Rochester. None have been completed.

“I would be involved in these issues no matter what the situation was,” Mr. Schumer said. “As a senator, you have some leverage because federal money is also part of it but you’re also not caught up in the minute-to-minute, day-to-day problems.”