Pension over-promises need renegotiating: Hubbard

Public pensions too generous, Romney adviser says
Public pensions too generous, Romney adviser says

Many state and local governments have too much debt and "too generous public pensions," said Glenn Hubbard, the Columbia Business School dean who advised Mitt Romney's 2012 presidential campaign and served as economic adviser to George W. Bush.

Detroit's bankruptcy is symptom of a nationwide problem of over-promises, Hubbard told CNBC's "Squawk Box" on Monday.

Glenn Hubbard Dean of the Columbia University Graduate School of Business.
Adam Jeffery | CNBC

"We need a national conversation on how to fix this."

(Special Report: Pandemic of pension woes plagues the nation)

"There are a lot of social promises here," Hubbard noted. "One is to taxpayers about services, one is to retirees and employees, and the other is to bond holders."

"When we promise more than we can deliver," he argued, "we have to renegotiate. And that's what's got to happen."

We need a national conversation on how to fix this.
Glenn Hubbard
Dean, Columbia Business School

Going forward, Hubbard said there's a role for the federal government to play in helping to prevent states and localities from denying fiscal realities. "At the federal level, we need policies that encourage state and local governments to move to reasonable accountings, so you don't lie about the future."

(Read more: How your city might pay for Detroit's money mess)

He also said that generating more economic growth would help "many of these [troubled] local governments."

By CNBC's Matthew J. Belvedere. Follow him on Twitter @Matt_SquawkCNBC.