Today, New York City is celebrating the opening of the first phase of the Second Avenue Subway, a project that’s been anticipated for nearly a century and that’s sorely needed to relieve overcrowding on the Lexington Avenue lines and to extend access to some very densely populated neighborhoods. But as exciting as the opening is, phase one is also a very modest-size project encompassing just three stations. The plan is, eventually, to extend it up into East Harlem, and potentially then either go farther south or swing west to provide crosstown subway service across 125th Street.

Any of this would be extremely useful to the city, but it’s far from clear that any of it will ever happen. That’s because even with $1 billion currently allocated in the Metropolitan Transit Authority’s capital budget for phase two of the Second Avenue Subway, it’s still badly short of the $6 billion that’s going to be needed.

New York state has a fair amount of potential financial resources at its disposal and could certainly come up with $6 billion to spend on extending the subway to East Harlem. But that’s naturally going to be a hard sell politically to the vast majority of New York state residents who don’t live in or regularly visit East Harlem.

The shame of it is that by the standards of other major world cities, the $1 billion the MTA already has budgeted should be plenty.

Foreign countries manage to build cheaper subways

The $6 billion price tag for phase two works out to $2.2 billion per kilometer. That would make it the world’s most expensive subway project on a per-kilometer basis, narrowly surpassing phase one of the Second Avenue Subway, which clocked in at “only” $1.7 billion per kilometer.

Now, building a railroad underneath an old, densely populated urban area is an inherently expensive undertaking. An old-style “cut and cover” construction method would never fly politically, and you have to deal with the fact that there’s already a whole bunch of infrastructure sitting beneath the ground.

But New York is not the only old and dense city that has built subway tunnels recently — it’s simply the most expensive. According to transit blogger Alon Levy’s compendium of international subway projects, Berlin’s U55 line cost $250 million per kilometer, Paris’s Metro Line 14 cost $230 million per kilometer, and Copenhagen’s Circle Line cost $260 million per kilometer.

At those prices, the $1 billion the MTA has in pocket would be enough to complete phase two with a few hundred million left to spare.

We could have more nice things if we built affordably

In many transit advocacy circles, it’s considered unfashionable to dwell on these questions of cost-effectiveness. The important thing, in this view, is simply to make the case for transit and try to get the money. After all, if the United States can squander $1 trillion invading Iraq, then surely we wouldn’t miss the $6 billion.

That’s fine as far as it goes, but it doesn’t go very far.

For starters: It doesn’t get you the $6 billion. Whether or not you think transportation infrastructure deserves more political support or military spending deserves less, the facts are what they are.

More to the point, making it cheaper to launch pointless invasions of medium-size countries wouldn’t be all that useful, since the monetary cost is really the least of the problems with a pointless invasion. By contrast, precisely because subway construction is genuinely useful, it would be good to do more of it. And one good way to build more subways would be to stretch our dollars as far as the French do.

At Parisian prices, the $6 billion the MTA is currently seeking for phase two would be enough money to build 15 miles’ worth of subway. That would permit a drastically more expansive vision of the Second Avenue Subway as a line that originates in the Financial District, runs north to Second Avenue, stretches all the way up to 125th Street, and then bends west to serve as a crosstown line uniting all of Harlem. Not only would this be a much more useful piece of transit service than a small extension to East Harlem, but also precisely because it would be more useful it would command more political support.

And, indeed, this has been Paris’s experience. The city’s greater success in controlling per-unit construction costs doesn’t mean it spends less money than New York — it means it spends more. Line 14 is just the first step in an ambitious proposal to spend $25 billion on a 120-mile addition of track to the Paris metro, involving four new lines and 68 new stations. If New York could build at those costs, the MTA could be proposing a comparably ambitious plan featuring new lines under Nostrand Avenue and Utica Avenue in Brooklyn, Northern Boulevard in Queens, and a circumferential Triboro RX line.

But with high costs per kilometer, you can only propose small projects, and small projects have limited constituencies that ultimately constrain funding.

What went wrong with the Second Avenue Subway?

Conservatives like to point the finger at labor unions as the villain for any kind of excessive government expense, but obviously France, Germany, and Denmark are all countries that have strong labor unions.

As Justin Fox has written, it’s possible that, paradoxically, the very weakness of American unions contributes to a dysfunctional political economy around infrastructure projects. In a country where the vast majority of workers are covered by a collective bargaining agreement, there’s little reason for labor as a whole to care one way or another about the size of public sector payrolls. In the United States, where unions are extremely weak overall but strong in coastal state governments and government contractors, there’s good reason for the overall labor movement to be supportive of a make-work system in which New York uses 25 tunnel-boring machine workers for a job that Spain handles with nine.

But as Josh Barro writes, the majority of the Second Avenue Subway’s price tag actually comes from the stations rather than the tunnels. The line is being built unusually deep for a subway tunnel, which doesn’t do much to change the basic logistics of boring a tunnel but does make excavation of station caverns unusually difficult.

This means the MTA could have saved a considerable amount of money by simply settling for smaller stations. The ones it is actually building have full-length mezzanines — effectively adding an entire second story to the station cavern — that, while nice to have, are not critical to the stations’ core transportation function. Deep stations in London, for example, simply lack mezzanines, and they work fine even if they feel a bit cramped.

The depth of the line itself is probably a more telling issue. The route along Second Avenue doesn’t cross other subway lines and thus doesn’t strictly need to be at extraordinary depth. But a deep tunnel minimizes conflicts with existing utility infrastructure. To build a shallower tunnel would require a lot of coordination between the MTA, which is a state agency, the city of New York, a bunch of different utility companies with different regulators, and perhaps the state itself. Getting that coordination done would require, in the first instance, direct political engagement and leadership to try to align incentives. But that’s leadership mostly in the sense of appointing technically competent people and listening to what they have to say, not the kind of helicopter grandstanding that leads to projects designed more to generate good photo ops than good transportation outcomes.

After that, it would require iteration and learning. The US city that’s doing the most rail construction these days is Los Angeles, and LA is getting better at it — delivering lower-than-normal costs for the United States (though still high compared with continental Europe) and laying out a published document of project management best practices to explain what it’s learned.

Governing well is hard

This is a lot of words about one project in one American city, but it does carry a broader lesson.

It’s relatively easy to look at an example of a foreign country that is doing something well — whether that’s Germany in using apprenticeships to connect young people to meaningful blue-collar work, Finland in supporting new parents, or Paris in building subway tunnels — and say that we ought to do it too. Certainly providing people with quality public services costs money, but the United States is a very rich country, and finding the money for something worthwhile is never impossible.

But this kind of discussion too often elides the real practical difficulties in implementing big domestic policies like those, and the ways in which the US system is uniquely bad and inefficient about doing so. Between the Second Avenue Subway, the $10.2 billion East Side Access tunnel for the LIRR, and the $4 billion World Trade Center PATH station, the New York City region is in fact spending a lot of money on upgrading its mass transit system. The money is simply not going to generate as much transit service as a comparable amount of spending would in Paris or Copenhagen, because New York’s institutions don’t seem up to the task of spending it as effectively. Improving is both possible and desirable, but it would take actual time and skill and effort.

By the same token, while we know now that it’s certainly possible to set up a Healthcare.gov website that works as intended, we also know that on the launch date the Obama administration had not, in fact, built such a website. That embarrassing governance failure undermined the president’s signature policy initiative in serious ways, with crucial long-term repercussions. And any big ambitious new progressive initiative is potentially vulnerable to this kind of failure. It’s hard to pass a law providing the money to create a new guarantee of universal access to high-quality pre-K. But it’s even harder to actually build and manage preschools that deliver high quality education.

Until places like New York and California — the bluest jurisdictions that are most open to the idea of taxing and spending to improve public services — get better at actually delivering those services in a cost-effective way, it’s going to be difficult to persuade residents of more skeptical jurisdictions that it makes sense to take the same agenda national.