New York’s political world was turned on its head late last week by a mapmaking expert from a prestigious college hours away from New York.

Jonathan Cervas, a postdoctoral fellow at Carnegie Mellon University in Pittsburgh, authored the state’s newly released, redrawn congressional and state Senate districts, which – barring a successful legal challenge – will take effect in this year’s elections and remain in place through 2032.

He was hired for the job by Acting State Supreme Court Justice Patrick McAllister, a conservative Steuben County judge who first ruled a prior set of Democrat-drawn congressional lines were drawn in such a way to benefit the Democratic Party, in violation of the state Constitution.

Democrats have targeted McAllister and Cervas for criticism, questioning their motives as they finalized the enormously consequential map that could help determine which party takes control of the U.S. House of Representatives next year.

So far, Cervas has declined requests for interviews about his New York mapmaking, saying he is treating the process as if he is involved in ongoing litigation. But he and McAllister provided a window into their respective thinking in a 31-page court filing early Saturday, with Cervas laying out his reasoning for many of the major choices he made – some of which will have ripple effects in elections for the next decade.

1. A GOP gerrymander? Judge pushes back hard

Yes, McAllister was elected on the Republican line, and he hired Cervas. And Republicans brought the lawsuit that got the original, Democrat-drawn lines thrown out. But McAllister forcefully pushed back against the notion that the new lines amounted to a “GOP gerrymander,” as some Democrats have suggested.

McAllister noted it wasn’t just his decision to throw out the previous lines. The mid-level Appellate Division agreed with him, as did the Democrat-dominated Court of Appeals, the state’s top court. The judge said all three courts reached the same conclusion because they “applied the applicable rules of law in as fair and impartial a manner as possible.”

“Unfortunately some people have encouraged the public to believe that now the court gets to create its own gerrymandered maps that favor Republicans,” McAllister wrote. “Such could not be further from the truth.”

Under the Democrat-drawn map, 22 of New York’s 26 congressional districts would have had a Democratic edge, based on how they voted in the 2020 presidential election. Just three would have been competitive seats, meaning the winning 2020 candidate received less than 55% of the vote.

Now, under the final map, 21 of the state’s 26 districts have a Democratic edge, but eight districts are considered competitive. The state’s congressional primary is set for August 23rd.

Among those that have raised McAllister’s political affiliation are Democratic Reps. Hakeem Jeffries of Brooklyn and Sean Patrick Maloney, who chairs the Democratic Congressional Campaign Committee. In a statement, Maloney said McAllister’s “legal reasoning was flawed and his motives were suspect.”

Maloney went as far as to hint at a possible lawsuit in an attempt to overturn or change the lines.

“Our country cannot continue on this undemocratic course where Democrats are held to a standard that Republicans openly defy or ignore,” Maloney said. “In the coming weeks and months we will continue fighting to get fair maps that reflect the will of the voters of New York.”

2. Bedford-Stuyvesant, Crown Heights kept whole

Cervas’ original proposal – which he released May 16th – set off a wave of criticism from the Black community and elected officials in New York City. The most heated remarks came from Jeffries, who was incensed by several Black neighborhoods being carved up among multiple districts – particularly Bedford-Stuyvesant.

Based on the criticism, Cervas made a number of changes that reunited predominantly Black neighborhoods in a single district, including Bed-Stuy and Crown Heights in Brooklyn and Co-op City in the Bronx.

“In the draft congressional map, I inadvertently split the community of Bedford-Stuyvesant while trying to create compact, legally compliant districts in Brooklyn,” Cervas wrote. “In the final version of the map, I have placed this community in full in District 8. Bedford-Stuyvesant is now the core of District 8, as has historically been the case.”

He wrote the same about Crown Heights in the 9th Congressional District, while Cervas placed Co-op City in the 14th Congressional District – and not the southern Westchester-based 16th Congressional District, currently held by Yonkers Rep. Jamaal Bowman, where it had been included before.

“Co-op City […] had to be moved out of the 16th because the population loss in upstate required CD 16 to take in more population to the north,” Cervas wrote.

Jeffries wasn’t impressed, calling the reunification of Bed-Stuy a “small step.”

“We will not let modest changes to a severely flawed draft map whitewash the violence done to communities of color throughout New York City,” he said in a statement.

3. Chinatown, Sunset Park reunited, but NY-11 becomes more Republican

When mapmakers draw up new districts, the state constitution requires them to take “communities of interest” – population groups that have similar social and demographic interests and have had a history of being marginalized – into account. They’re not supposed to be split among multiple districts, which can dilute their voting power.

But Manhattan’s Chinatown and Brooklyn’s Sunset Park – both home to large Asian populations – were on the verge of being split apart, despite being paired together for the previous two decades. Cervas had them in different districts in his initial proposal.

He changed his mind in his final map, shifting the Brooklyn portion of the 10th Congressional District around to join Sunset Park, Red Hook, Carroll Gardens, Park Slope and Gowanus with Lower Manhattan, including Chinatown.

But with districts that require equal population, that shift had a ripple effect – pushing some Republican-heavy precincts in Bath Beach and Bensonhurst into the Brooklyn portion of the Staten Island-based 11th Congressional District, making it a safer seat for the GOP and incumbent Rep. Nicole Malliotakis.

4. Manhattan gets a major shake-up

While Cervas took steps to honor some traditional districts in the outer boroughs, he was of a different mind in Manhattan. For decades, Manhattan’s congressional districts split east-to-west, meaning the East Side and the West Side were generally in different districts.

That’s no longer the case. Despite a major push from the Jewish community, Cervas stood firmly behind his plan to simplify the Manhattan districts. That includes Rep. Jerrold Nadler’s current 10th District, which had been a serpentine-shaped district that connected heavily Jewish communities in Manhattan to those in Brooklyn.

“(While) this is a hard choice, I do not find a compelling community of interest argument for changing the configuration of Manhattan congressional districts in the proposed map,” wrote Cervas, who noted the East and West Sides of Manhattan “do not appear to be as strongly distinguished in terms of economic and demographic differences as they once were.”

Now, Manhattan will be split into three simply shaped congressional districts. Lower Manhattan will be in the new 10th District that stretches into Brooklyn; the 12th Congressional District stretches from Midtown to the upper reaches of Central Park; and the 13th Congressional District captures the northernmost portion of Manhattan, combining it with part of the Bronx.

Already, it’s set up two major showdowns: Nadler and fellow veteran Rep. Carolyn Maloney have both declared for the new 12th District alongside Suraj Patel; and there’s a Democratic free-for-all in the 10th District that includes former New York City Mayor Bill de Blasio, Assemblymember Yuh-Line Niou and Westchester Rep. Mondaire Jones —  all of whom have officially announced their campaigns.

5. Long Island splits north, south shores

While Cervas wasn’t persuaded to return Manhattan to an east-west split, he was convinced to split up Long Island’s north and south shores.

In his original map, Cervas had proposed three separate Long Island districts that included both shores. But several civic groups pushed back, including the League of Women Voters’ Long Island chapter, noting that the issues facing the north shore aren’t necessarily the same as those on the south shore. Among the issues raised: Major storms often hit the two shores differently, mandating a different response.

So Cervas shifted his proposal around, creating a new 2nd Congressional District that runs along the south shore of Suffolk County (and a small piece of Nassau), and creating a 1st Congressional District that runs along the north shore before curving around to capture the entire eastern tip of Suffolk.