Voters on Staten Island—long the only Republicn corner of New York City—have turned their Republican Congressman Dan Donovan out of office. New York’s 11th District—which the island shares with a couple of neighborhoods across the Verrazanno Bridge in Brooklyn—was the last part of the city to be represented by a Republican in the U.S. House. Although Democrats in the district outnumber Republicans by a 2-to-1 margin, Donald Trump won 58 percent of the vote there in 2016. The President retains some popular support on the island, his policies less so.

The surprising victory of Democrat Max Rose signals that Staten Island is genuinely a swing district—something that New York Democrats have precious little experience with. The combination of gerrymandering and “big sort” demographic shifts created a sort of district-by-district one-party domination in New York State that has resulted, at least within the city, in neither party knowing how to run in competitive elections.

In a deep-blue city like New York, political posts are handed down like family heirlooms. More politicians leave office in handcuffs or a pine box than because of voter will. As a result, the county—or, in NYC-speak, borough—political organizations are hollowed out. They’re less machines than automatons that go through the motions with little if any involvement from actual people.

A Purple Heart military veteran, Rose was recruited to move to Staten Island and run for office by the Democratic Congressional Campaign Committee. His campaign messaging included complaints about “both sides” and swipes at Mayor Bill DeBlasio, a focus on opioid addiction and an allergic reaction to Medicare-for-All, with a wonkish focus on expanding access to health care within the framework of the Affordable Care Act.

Centrist Democratic consultants will point to Rose’s campaign messaging as a lesson for Democrats in 2020, but there’s probably more of an organizing lesson to be learned. The Rose campaign activated hundreds of volunteers who canvassed the district to identify over 86,000 likely voters, and then turn them—and more—out to win with a decisive 52.8 percent of the vote.

Rose has staying power, and Staten Island’s political landscape will never be the same. The election is no less than a political realignment in New York’s most conservative borough, which can no longer be written off as Republican territory. Now comes a day of reckoning for both parties’ local organizations, and some badly-needed soul-searching for New York’s unions about how they approach the question of “electability” and “sure-things.”

WHEN DISTRICTS REALIGN, both parties’ old orders are threatened.

The Republican party operation on Staten Island was once a nigh-unstoppable machine that was crucial to the election victories of Ronald Reagan, Alphonse D’amato, and Rudy Giuliani. In recent years it’s been dependant on low-turnout special and midterm elections to retain its competitive edge.

For four decades, the Staten Island GOP was led by Guy V. Molinari, the politician who first flipped what had been a reliably Democratic congressional district in 1980—the year of Reagan’s presidential election—before moving on to become Borough President. Molinari passed away this summer, but his party machine never outgrew him or his grudges. He openly feuded with Representative Donovan as well as James Oddo, the current Republican Borough President. In a healthy organization either of these elected officials would be their party’s official leader. Instead Molinari threatened them both with primary challenges. He encouraged his protege, ex-con ex-Representative Michael Grimm, to run against Donovan for his old seat. That bruising primary campaign fatally damaged Donovan’s credibility as a moderate by compelling him, as Republican primaries do, to move further to the right.

One party operative publicly blamed “years of neglect and years of trying to make the county organization smaller and subservient to its leaders” for the historic loss of Molinari’s old seat.

Lawn signs ordinarily might not be an indication of anything significant, but it was notable how few Dan Donovan lawn signs could be seen around the island—especially compared to Max Rose’s and even the faded Michael Grimm signs from his failed primary bid. I don’t know a single friend or neighbor who had a Donovan volunteer knock on their door or call on the phone. None of my fellow commuters could recall seeing the Donovan team passing out campaign lit at the Staten Island Ferry, which is the barest minimum that any local political effort must do.

We all assumed that the Republicans had some secret weapon or really reliable internal polling, but the post-election public recriminations in our local paper of record, the Staten Island Advance, confirm that there was nothing; just a misguided assumption that the rubes would keep on voting Republican in sufficient numbers.

It is all but certain that there will be a significant personnel shake-up at the Staten Island GOP.

On the Democratic side, the county committee has been a baffling mess. Earlier in the year, one of Staten Island’s few elected Democratic state legislators, Matthew Titone, decided to forego re-election for his safe seat in order to run for the borough-wide position of Surrogate Judge. Party chairman John Gulino strong-armed his county committee to deny Titone the party’s endorsementpossibly because Titone is an out gay man, and Gulino has some notion that such a thing is political poison in Staten Island’s more conservative enclaves (or it could be for an even dumber reason that we’ll never fully understand).

Nonetheless, Titone trounced the party’s hand-picked mediocrity in the primary and cruised to victory in the same general election that saw Rose upend the borough’s political calculus. In the interim, the rusty S.I. Democratic machine failed to even file the necessary paperwork for its down-ballot judicial nominees, allowing the Republicans to win those races free from competition.

In 2014, with Michael Grimm running for re-election under the cloud of a 20-count indictment, the SI Dems allowed the Brooklyn machine to fob off an inarticulate city councilman from the other side other side of the Verrazzano who bumbled his way to an ignominious defeat. Before that, they ran the son of the crook who had lost his seat to Molinari four decades ago.

Clearly there are going to be big changes in the thoroughly-discredited Democratic county committee, and Rose would be the natural party leader. One close observer of S.I. politics speculates that Rose’s chief of staff, Kevin Elkins, will replace Gulino and turn the party into the kind of GOTV organization that put Rose over the top.

MOSTLY ABSENT FROM THE STORY of Max Rose’s ground-breaking victory are unions. The New York state AFL-CIO endorsed Donovan, the Republican incumbent. Although 1199 SEIU and the Staten Island-based local 1102 of the Communications Workers put a lot of feet in the street on Rose’s behalf, the rest of the labor movement took the cautious approach of issuing paper endorsements of the GOP incumbent who was favored to win re-election.

Their calculation was as simple as it was cold. Donovan picked up the phone when they called. He could do them small favors and GOP leadership gave him permission to vote no on the really big bad bills like the billionaire tax cut and health care repeal. That those bills came to the floor at all was because Donovan caucused with the death cult that is the congressional Republican party, but his permission from Paul Ryan to avoid getting his hands dirty allowed him to avoid hardcore opposition from the unions. For the unions, the question was why risk losing access to a flawed Republican when a good Democrat who wins without labor’s backing can be expected to forgive and forget (and count on their backing for re-election)?

Staying away from Rose’s long-shot campaign was hardly the most embarrassing inaction by New York’s unions this political season. The most electrifying primary election in the country saw newcomer Alexandria Ocasio-Cortez defeat 10-term congressman Joe Crowley. The idea that the fourth ranked Democrat in Congress and chairman of his county’s Democratic machine could be crushed by a 28-year-old democratic socialist with no financial war chest stunned the political establishment. And in New York unions are very much a part of the political establishment. With nearly a quarter of New York workers belonging to one, unions remain powerful and influential—and exceedingly cautious when it comes to political endorsements.In that primary, the unions reflexively endorsed the incumbent, Crowley.

Nationally, 2020 likely will see more left wing primary challenges in deep blue districts—and the general election will see the last of the moderate Republicans in the fight of their political lives. Unions that back centrist Democrats and moderate Republicans will have some difficult decisions to make.

[This article originally appeared at The American Prospect.]