When does a local education fight become a national bellwether? When it touches a policy lightning rod, scrambles partisan allegiances, and involves political actors who stand in for whole political ideologies.

And, sure, it helps when the locale staging the fight is New York City.

New mayor Bill de Blasio made waves last Thursday when his administration withdrew three agreements that would have allowed public charter schools to share space with district schools in public school buildings. The affected schools are all part of the Success Academy network of schools, which was founded by Eva Moskowitz, a former New York City councilmember. These “co-location” agreements were approved last October, under previous mayor Michael Bloomberg’s administration.

While some of the city’s public charter schools operate out of privately owned buildings, all Success Academy schools are co-located with district schools. According to Ann Powell, communications director for Success Academy, the network sees this as a “civil rights issue…[our] parents shouldn’t have to pay rent. Our students are public school kids.” Indeed, while public charter schools are free from some of the regulations that district schools must follow they are still publicly funded.

But de Blasio—and others—have argued that this “abhorrent” arrangement amounts to giving public charters a free ride. Leo Casey, Executive Director of the Albert Shanker Institute and a former vice president of New York’s teachers union, suggested that it’s about more than just rent: “Eva Moskowitz’s schools are a particularly egregious case…every school is co-located and as a co-location, what they get for free is not only the building, the facilities itself, not only the space that’s up to code, etc. They get the food [and] janitorial services.”

When asked about these costs, Powell noted that public charter schools receive $13,527 in public funds for each student. Traditional district schools receive just over $19,076 in public funds for each student.

In response, Casey noted that the city’s Independent Budget Office has calculated that the gap in public funding may be somewhat narrower in recent years—and may slightly favor public charters housed in public buildings. They also found that public charters paying for private facilities receive significantly less per student funding than district public schools. Charter advocates have disputed the IBO’s analysis (PDF), arguing that they don’t take district schools’ large pension costs into account.

Unsurprisingly, the fight was big news in the New York metro area.

But since the national media has anointed de Blasio as one of the spokesmen for a resurgent Democratic Party progressivism, his moves attracted much broader attention. House Majority Leader Eric Cantor accused him of waging a “war against kids” and House Republicans promptly announced a committee hearing on “The Role of Charter Schools in K-12 Education.”

While there’s nothing particularly surprising about Republican opposition to a progressive mayor’s approach to urban education policy, their attention actually has more to do with intra-party Democratic politics. After all, De Blasio and Moskowitz are both Democrats—though their personal and ideological differences are vast. Some Republicans, following Cantor’s lead, have been probing at public charter schools—and school choice programs more broadly—as a wedge issue with potential for causing dissension amongst Democrats. The current battle in New York City provides some evidence supporting their approach.

There is no love lost between Moskowitz and the mayor. De Blasio singled her out for criticism while campaigning, arguing that she had “to stop being tolerated, enabled, [and] supported” by the city’s Department of Education. As Casey sees it, de Blasio revoked the co-location agreements to “lay down a marker” that would send a signal to all New York City public charter operators.

But it’s a mistake to see last week’s public charter school fight as simply the latest twist in a personal grudge match. Nor is the faceoff as simple as a battle between public charters and teachers unions. The union in New York City—the United Federation of Teachers—actually runs its own public charter school in Brooklyn.

The rancor between de Blasio and Moskowitz has at least some roots in substantive education policy disagreements. During his campaign, de Blasio promised to roll back Bloomberg Administration policies on public charter schools. He began fulfilling that pledge one month into his term when his administration reallocated $210 million from a public charter school expansion fund. This—among other moves—has put him at odds with many New York Democrats, most notably Governor Andrew Cuomo (who responded Monday with a promise to provide state funding for the displaced schools).

Indeed, interviews for this story turned up a wide range of responses to the de Blasio administration’s move. Success Academy’s Powell touted its benefits for kids: one of the schools the mayor is evicting had the highest-performing 5th graders in New York’s state math assessment in 2013. There weren’t just the highest performing in the city, she repeated. They were first in the entire state. “It’s just a little odd that we can’t find some space for a few hundred minority kids…80% of them are on free or reduced lunch, and nearly all are high-performing. You’d think that New York could use more schools like that.”

A New York Democratic Party consultant, who asked to remain anonymous because of the intra-party nature of the debate, called de Blasio’s revocation of “both personal and ideological.” The consultant went on: “de Blasio is deeply hostile to the idea of charter schools. He is deeply hostile to the education reform movement as a whole…There’s a spectrum in the Democratic Party, where you have people like Barack Obama and [Colorado Governor] John Hickenlooper and even Cuomo…who believe that education reform and charter schools can be a positive force in public education.”

Asked to elaborate, the consultant added, “[De Blasio] is someone who just subscribes to the traditional teachers union based belief that anything outside the old school public education, any innovation, any reform, is a bad idea.”

Meanwhile, Casey, who serves on the board of a New York public charter school, cheered the mayor’s decision: “What’s happened in NYC now is that [Success Academy] is reaping what they sowed.” He argued that Success Academy and other similar public charters had provided cover for the Bloomberg administration’s efforts to undermine collective bargaining and close struggling district schools. In Casey’s eyes, “no-excuses charters” like Moskowitz’s take an approach “that is indistinguishable from Walmart’s” when it comes to employee bargaining rights.

Sam Chaltain, author of the forthcoming book, Our School: Searching for Community in the Era of Choice, suggested that co-location might sometimes be effective, but noted that it could invite uncomfortable comparisons between schools: “in the worst case, it could make one school feel inferior.”

When I asked him if this sort of division could cause trouble for Democrats on a national level, Bellwether Education co-founder and partner Andrew Rotherham, a prominent education writer and former Clinton Administration official, laughed and channeled Will Rogers: “That’s the 64 thousand dollar question. Look, this is the Democratic Party, so if you’re looking for unity or coherence, you’ve got to look somewhere else.”

Maybe this is just another manifestation of Democratic disorganization. it spread beyond the five boroughs—and into national partisan politics?

I asked Chaltain if he thought public charters could be a productive wedge issue for Republicans. He demurred: “The overall climate of what people think about charters and school choice varies so much from city to city.” This is certainly true. State charter laws vary widely across the country—and eight states have no public charter schools at all.

What’s more, public charter schools are a very small slice of the American education system. Out of the nearly 50 million K-12 students in American public schools, less than 2 million attend public charters. There are more students in Catholic schools. Indeed, there are nearly three times as many K-12 students in private schools than in public charters. The upshot: it’s hard to see how this very small population could drive enough controversy to sustain a national political discussion.

But focusing on the size of the American public charter sector might be missing the point. Problematic ideological splits are usually rooted in principle—not pragmatism. Chaltain cautioned, “I do think it’s a big intra-Democratic Party battle, and I think it’s a split in the value proposition about public education.”

This gets at why education inhabits a unique space in American politics. Because it is deeply implicated in American democratic and meritocratic ideals, it is permanently controversial (consider, for instance, the persistent, rumbling fights over implementation of the Common Core State Standards).

Nonetheless, education rarely grabs headlines or news cycles the way that other, more dramatic topics regularly command. Check cable news: for every one segment covering ongoing education fights, you’ll see dozens covering the situation in Ukraine. In part, this is because the education system is just too large for a targeted national discussion. Attempts at comprehensive education reform usually span federal, state, and local governing institutions, as well as myriad union contracts and funding sources. Which makes them complicated. And nothing kills political controversy like complexity, so most education politics flareups happen at the state or local level—where the arguments don’t need to be as broad.

In other words, education politics has a unique dynamic; it has permanent political potency, but can’t usually hold national attention for long. Public charter schools may be locally controversial, but it’s hard to imagine them driving a national campaign to Democrats’ detriment.

What’s more, education politics can be a double-edged sword. Educational ideology cuts across party lines—a rarity in twenty-first century American politics. For instance, the fight over the Common Core has made allies out of Jeb Bush and Barack Obama. And while public charter schools challenge Democrats’ unity, Republicans education factions may be more consequential.

Consider the other plank in de Blasio’s mayoral campaign: universal pre-K. De Blasio promised to fund universal pre-K in New York City with a tax hike of about 0.5 percentage points on incomes of over half a million dollars each year, but hasn’t been able to push that through the legislature in Albany (which must sign off on all NYC tax increases). The program remains in a holding pattern as the mayor fences with New York Governor Andrew Cuomo, whose counterproposal offers a slower path to universal access and relies on existing state revenues.

Republicans are in a tough position on pre-K. While the American public, nearly all elected Democrats, and a majority of Republican voters (PDF) support expanded access to high-quality early education, Republican officials are split. Last summer, the reliably conservative U.S. Chamber of Commerce co-hosted an event with the Center for American Progress to call for increased American pre-K investment. A few months ago, the House and Senate introduced bills aiming to make pre-K universally available for families living at or below 200 percent of the poverty line. The House bill has two Republican co-sponsors and widespread Democratic support. And while Republican governors like Michigan’s Rick Snyder have fought hard for larger investments in early education, many in the party remain opposed.

In other words, high-quality pre-K is a much more powerful political issue than public charter schools. While American early education policy is heavily shaped by a number of federal laws, charter policy is almost entirely determined at the state level. This, by the way, is why public charter schools’ quality varies widely from state to state. A recent Stanford study (PDF) found that public charters in Washington, D.C. and New York substantially outperformed similar district schools, while public charters in Nevada and Texas lagged far behind their district peers.

So while it’s tempting to frame the fight in New York as a perilous fight between Democratic education reformers and “the de Blasio wing” of the party, public charter schools are just too local to drive a national political conversation—let alone a serious civil war within the Democratic party.

Of course, even though public charter schools aren’t a promising plank for national political leverage, they’re still plenty controversial. The lightning rod isn’t going away, cautioned Chaltain. “The school choice genie is out of the bottle…To me, the only question is how can school choice unleash a virtuous cycle that raises the tide of educational opportunity?” And while that’s a conversation that’s both less exciting and more uncomfortable than the current debate in New York, it’s almost assuredly a more productive one.