The judges ordered Mr. Cervas, a postdoctoral researcher at Carnegie Mellon University who also advised Pennsylvania lawmakers to sign new maps there this year, to draft replacements immediately. Justice McAllister then postponed the Congressional and Senate primaries from June to August to accommodate the changes.
Perhaps the most startling realignment occurred in Manhattan, an island long divided on an east-west axis. The special master suggested dividing it north-south instead, throwing both Mr. Nadler and Ms. Maloney into the 12th congressional district after serving side-by-side for three decades. (The change cut off the top half of one of the city’s most bizarrely shaped districts that had led to accusations of gerrymandering.)
Allies of both candidates, including party leaders, spent the afternoon trying in vain to convince the other to change course and run to the newly reconfigured 10th district, which runs from lower Manhattan to Brooklyn Heights, Park Slope and south to the ultra-Orthodox. Jewish community in the Borough Park neighborhood of Brooklyn.
At least one prominent Democrat from Park Slope was already on the phone on Monday about a possible candidate for the seat: Bill de Blasio, the former mayor, according to a de Blasio adviser and another person familiar with his outreach.
Mr. Nadler, 74, who as chairman of the House Judiciary Committee was central to the push to impeach former President Donald J. Trump, quickly made it clear that he had no intention of destroying the Manhattan portion of his current district. abandoned, where he has lived on the Upper West Side for decades.
In an interview, Ms. Maloney also seemed ready for a fight, praising her own long track record as leader of the House Oversight and Reform Committee.
“I’m sorry,” said Ms. Maloney, 76. “We’ve been colleagues for a long time.”
But she added that she had no intention of moving to another seat.
“It’s really off the table for me,” she said. “I have my own house in the neighborhood and I’ve lived there my entire adult life.”