When a politician commits a gaffe on the campaign trail, it’s usually an excuse for the news media to fire up the outrage machine. Every once in a while, however, a gaffe comes along that lets the truth out — however unintentionally.

Instead of another exercise in mockery and vitriol, it’s a teachable moment.

That’s what recently happened to Hillary Clinton.

Stumping for gubernatorial candidate Martha Coakley, Ms. Clinton let slip the kind of comment that can launch a thousand ships of criticism. “Don’t let anybody tell you that, you know, it’s corporations and businesses that create jobs,” she said.

Not long after, Ms. Clinton walked it back, of course. “Our economy grows when businesses and entrepreneurs create good-paying jobs here in an America,” she explained, “where workers and families are empowered to build from the bottom up and the middle out — not when we hand out tax breaks for corporations that outsource jobs or stash their profits overseas.”

Still, Republicans like Jeb Bush pounced on her original remark. Certainly, a politico as polished and experienced as Hillary Clinton knows she’ll take her lumps even after making a clarification.

But Ms. Clinton’s poor phrasing accidentally revealed an important insight.

As Harold Meyerson observed at the Washington Post, some of the biggest businesses Ms. Clinton slammed are among America’s biggest banks — banks run by some of Ms. Clinton’s most reliable backers.

Yet there’s something about Ms. Clinton’s criticism that’s even more important than the hypocrisy that fact implies. When big corporations with close government ties fail to boost broad-based economic growth, including job growth, it’s not really because Republicans have lightened their tax burden.

A more significant factor is the way those corporations can game the regulatory system and benefit from political patronage.

Inside the bubble of cronyism, profits can be generated in a manner that the free market hardly gets to access.

It’s a problem that’s visible in some of America’s most important financial institutions. Just consider the stock market, where big corporations continue to make a killing, although the fundamentals of the economy, including hiring and job growth, continue to be weak.

Ms. Clinton doesn’t want to admit it, but the structural problems with crony capitalism can’t be boiled down to the “trickle-down economics” that defined the bygone Reagan era.

Back in the 1980s, the financial system was much less centralized than it is today. What’s more, government regulation of that system was simpler and more streamlined.

Now, layers of official and unofficial rules give banks, health care firms and other massive corporations ample opportunities to cash in on the buying and selling of access that defined our politics in the wake of -well, the presidency of Bill Clinton.

— Orange County (Calif.) Register