Forty-six seasons ago, Mayor Wagner, Robert Moses, and team owner Walter O’Malley broke a borough’s heart when the Brooklyn Dodgers slipped away to the Left Coast. On Wednesday, Mayor Bloomberg and developer Bruce Ratner took a step toward healing that heart with the announcement that the New Jersey Nets, Eastern Conference champions for two years running, hoped to be moving to a new stadium a mile from where once stood Ebbets Field.

The proposed move of the Nets to Brooklyn is indicative of a shift. The California that beckoned the Dodgers is no longer seen as the land of opportunity. Brooklyn is again being recognized as a great American city with a future even brighter than its illustrious past.

Much of the credit for this shift from a borough sports franchises abandoned to one that may soon be home to the Nets and already hosts the Mets’ single-A affiliate, the Coney Island Cyclones, can be attributed to Mayor Giuliani. His success in reducing crime inspired investment and development, midwifed by pro-growth policies from his City Hall. Credit also goes to Mr. Ratner, who in constructing MetroTech and the Atlantic Mall helped revive the borough’s long-suffering downtown, paving the way for his latest coup.

This resurgence has been solidified by an influx of new Brooklyn residents who in the past might have lived at Greenwich Village, Gramercy Park, or the Upper West Side. They now choose to raise their families in wonderful neighborhoods like Park Slope, Cobble Hill, and Victorian Flatbush. They’ve brought with them first-rate restaurants and, increasingly, shopping.

Much work remains to be done before the plans announced Wednesday evening are realized. Mayor Bloomberg and the City Council need to recognize that this development is much in the city’s interest, but at the same time ensure that Mr. Ratner maintains his pledge to spend little of the taxpayers’ moneys. We reserve judgment for the moment on the questions of condemnation and eminent domain, but as a general matter the acquisition of the Nets is one part of a larger effort going on citywide — from ground zero, the Hudson River Park, and the Far West Side in Manhattan, to Long Island City in Queens and Greenpoint in Brooklyn and the mayor’s proposed new park on Fresh Kills in Staten Island, to say nothing of the construction projects that would be undertaken should New York be chosen to host the 2012 Olympics. These developments are broadly encouraging.

In retrospect it may seem surprising that Brooklyn, with a population four times that of St. Louis, could have been ignored by high profile private investment for so long. But the county of Kings has not seen such high times since the days of trolley-dodging, and its own basketball team would be a fine addition to the borough’s Renaissance.