Against my better judgment I’m going to weigh in on this Cory Booker story. As you probably know, Booker appeared on Meet the Press yesterday and pronounced himself “nauseated” by the Obama campaign’s attacks on Mitt Romney’s record with the private equity firm Bain Capital. In a follow-up YouTube that looked like the kind of video hostage-takers make their victims record, Booker walked back the comments, saying that Mitt Romney’s record at Bain Capital is fair game for scrutiny, and that Romney “is not being completely honest with his role and his record even while a businessperson, and is shaping it to serve his political interest.”

None of this really interests me, but it is worth understanding Booker’s knee-jerk response against attacks on private equity. Steve Benen writes here that “plenty of Booker’s constituents work in private equity, so it stands to reason he’s going to defend the industry.” The median household income in Newark, New Jersey, where Booker serves as mayor, is around $36,000 a year, almost half of the rest of the state. 25% of the population sits below the poverty line. There are a couple more suburban parts inside the city limits, but the idea that Newark is teeming with rich private equity kingpins is just misguided. To the extent that “constituents” of Booker’s work in private equity, you’d have to be talking about his donors.

But more than that, Jason Kelly explains how Booker, and most other big-city mayors, have an ongoing love affair with private equity in a time of depressed investment from state and local governments.

The answer: New Jersey has a lot riding on private equity.

The state’s pension system in December agreed to a sweeping $1.8 billion deal with private equity giant Blackstone Group that will comprise investments in real estate, energy and debt funds. That brought New Jersey’s total commitments over 12 months to $2.5 billion to Blackstone alone, the most Schwarzman’s New York firm has attracted from a single investor in a single year since its creation.

There’s another reason Booker may have spoken up. While he doesn’t control New Jersey’s state pension, as the mayor of a big city Booker has a deep interest in economic development. The Private Equity Growth Capital Council was quick to seize on that angle. In an email this morning, the industry’s main lobbyist, amid a campaign to defend its practices, noted that New Jersey drew $3 billion in private equity investment last year into the state economy.

In fact, Booker alluded to this right after saying he wouldn’t indict private equity, noting that “Especially that I know I live in a state where pension funds, unions and other people invest in companies like Bain Capital.”

This is not limited to New Jersey; practically every state in the union uses private equity, particularly through their large pension funds. This creates a symbiotic relationship between state and local governments and vulture capitalists. The pension funds then invest in local economies, fattened by the higher returns they get from their entrusting of funds to private equity. This allows these firms, which specialize in stripping down companies and turning over profits, without regard for the workers they leave behind, to get inoculated by the political class, who want to keep this game going.

The other way to go about this is to have a sustainable level of investment at the state and local level, so that we don’t rely on outsized returns from predatory asset-stripping for whatever investment we can manage. But that would require a sufficient level of taxation, and the people who fund campaigns have put the kibosh on that. This is a bipartisan problem, and it’s how you get Cory Booker tripping up on his campaign surrogate duties. It’s hard to make a villain out of your contributors.