The best way to get the lay of the land in American politics is to ignore the biggest word being bandied around and pay attention to where the money is nervous.

The big word is, of course, "communist. In the early hours following three candidates endorsed by New York City Mayor Zohran Mamdani sweeping their Democratic primaries this week, two of them ousting sitting members of Congress, the President used his social media platform to say the country would never become a communist nation, then added a day later that the communists were "finally making their move," which he said he had been working on for a long time. He congratulated "3 solid Communists" for passing the finish line, he sarcastically intoned, and reminded people that he had a "spotless" endorsement record on the same night.

It was a show-stopper and it did just that. But the framing is deceptive and it is. None of the three winners former city comptroller Brad Lander (Lower Manhattan and Brooklyn), state lawmaker Claire Valdez (Brooklyn and Queens), and organizer Darializa Avila Chevalier (uptown) are proponents of communism, which calls for the state to take all private property. Two belong to the Democratic Socialists of America; Lander, a self-described liberal Zionist, has been a member for years, but exited the organization years ago. Their platforms include rent freezes, free buses, public childcare, increased taxes on the rich and on corporations, and in Avila Chevalier's case, eliminating the immigration enforcement agency. All that alarming you can find you can find. It is nowhere near the gulag, and equating the two is far from analytical.

Therefore, put the label aside. The real juicy meat is found beneath: a tale of a party at war with itself, and a tale of whether the economics of what this movement are selling can stand up to a city with feet.

It began with the civil war, which erupted in an unusual frankness. The most quotable Democratic strategist of the past four decades, the man who made his job to remind his party that elections are won on the economy, went on his podcast and, in language that he did not bother to mince, declared that he's "done. He was calling for the kind of schism that he described as a split the winners are not even real Democrats; he urged the establishment to sit down and negotiate a formal split. He has singled out Avila Chevalier as someone he would not seat in the caucus even if she wins in November, citing past statements of hers that he found indefensible, and he has drawn his sharpest criticism not on tax policy but on Israel saying he has “no room in my caucus” for anyone who questions the right of Israel to exist. He took care to distinguish that from general criticism of the government policy of Israel, which he said he welcomes. That matters, and that's the fault line that has been more responsible than any economic argument to dividing the American left over the last two years.

The party's real leadership responded with prudence befitting those who can count. The House minority leader, a New Yorker himself who was booed by supporters at one victory party and chanted at by others, “you're next” played down the entire episode as “basically three seats in deep-blue districts,” but said the mayor has “work to do” in dealing with Congress. Less inhibited were other progressives. One California congressman stated emphatically that there is now "a new party. There is a common thread in that sentence: a sense, from opposite emotional ends, that the old coalition is no longer viable, as the strategist says in his schism talk and the activists chant.

As usual, Republicans are thrilled, and they certainly aren't concealing it. An Ohio senator cautioned his own party, saying there was a socialist uprising among the opposition. Flowers and a condolence card were sent to him by the party's House campaign arm. This is not subtle, and it lets you know how the next eighteen months will play out: every competitive race in this country will be defined by an attempt to pin Mamdani's face on candidates who never set foot in Brooklyn and the word “socialist.” But whether it's effective anywhere beyond a few young, high-priced urban districts remains the big question that should concern Democratic strategists much more than any post by a president on social media. The strength of the movement is real, but the geographic range is small. The areas it has just won were never going to be in question in a general election. The districts that elect the leaders of Congress bear little resemblance.

Now the part that the markets do care about, and why the word "communist" is a non-starter in a serious debate.

The City of New York is not a poor city working on the fringes. It is the financial capital of the world, and it finances itself in such a way that it makes its own financing very vulnerable to an agenda adopted by this movement. The city receives about forty percent of its income-tax revenue from the top one percent of its filers. It's a remarkable focus, and it works to both sides of the argument. It's what the rich can pay more for, supporters argue. That's what critics say is why you don't want to give them a reason to leave: a revenue base that thin is a revenue base that can move.

The numbers on the table are not little. Some of the pillars of Mamdani's program have been raising the city's highest rate of income tax from 3.9 percent to 5.9 percent (and, with the state rate, the top marginal rate would hit the country's highest at seventeen percent); increasing the corporate tax rate from 7.25 percent to 11.5 percent; and imposing a surtax on those with a million dollars or more in income. The mayor was handed a deficit of about twelve billion dollars for two fiscal years a fiscal reality that none of the lofty rhetoric could change. Obviously out of City Hall's control, much of the tax agenda is in the hands of the governor and state legislature in Albany, and the governor has already put cold water on some of the most ambitious elements. There is a chasm between promising and delivering, and that's where most radical municipal agendas die.

The most contested element of the economics is the “flagship” proposal, that of a rent freeze for about two million stabilized apartments. Those buildings have been costing more to run than the rents they have been able to command for years; one lender estimates the delinquency rate on loans for stabilized buildings at nearly eleven percent, and only under one percent for market-rate buildings. Lock up the rent, you don't end the math, you ramp it up. The textbook answer, at which even most economists converge, despite disagreeing on many other issues, is deferred maintenance, withheld units and a slow deterioration of the very housing the policy is designed to preserve. Those who stand to lose the most in that scenario are not the rich, who have alternatives, but the middle and lower-income tenanted farmers who don't.

Here a sober, worldly reading is more helpful than panic or celebration. We have already witnessed a variant of this movie in other countries and other decades. Left-populist insurgencies tend to come to the same end: capital is mobile, talent is mobile, and the rich are the most mobile of all. Already, one grocery-chain owner has suggested that he might close down, and a prominent eyeglasses founder has indicated that he will remain in the business but will see others exit. Some of that was posing in a budget negotiation and the much-heralded exodus of the rich, which was predicted loudly before Mamdani even came to office, hasn't happened in any dramatic way. The city's labor force participation and jobs have remained strong. But the warning signs aren't make-believe, either. City real median household income declined by nearly five percent between 2019 and 2024, and increased slightly at the national level. Private-sector employment still has not recovered to where it was before the pandemic. This is a slowdown in the economy expected to finance an expansionist agenda and it is a tension that cannot be fixed with a hashtag.

The international side to the domestic shouting is what gets lost. The municipal-bond market and international investors are paying close attention to New York as they would pay attention to any large issuer that all of a sudden depends on a narrow, cyclical tax stream to support ongoing spending. Credit-rating agencies are not interested in ideology; they're interested in whether or not the revenue projections will be met if Wall Street has a bad year. A city that relies on its wealthiest residents and most lucrative businesses for the majority of its tax revenue, and then prices itself out of their world, is conducting a true experiment in elasticity. It will not be known for years and it will be read far outside the five boroughs, as every mayor and finance minister, playing with a similar scheme, will use New York as the test case.

Here, then, is the honest summary, sans cartoon. A five-point left did take three safe seats and it terrified its own leadership to the point where one of its most famous voices is demanding a divorce. A President took up an opportunity to campaign against socialism for the next two years. Then beneath the din lies a cold, unfeeling query: Can a small, mobile tax base be taxed and regulated as this movement desires without the base walking away? The answer to that question is not a communist one. Arithmetic is at the heart of it and arithmetic, unlike a slogan, eventually sends a bill.