"Something's got to give," he said. "We have to find a better model."

WashPost: “Greenspan urges action on Social Security”

But in some of his most forceful language on the subject, Greenspan argued that lawmakers should consider introducing private accounts because the current Social Security system is outdated. He repeated that he believes the nation has promised retirees more benefits than it has the resources to deliver. And he was explicit about the potentially negative economic consequences of trying to meet those obligations.

If nothing is done, Greenspan predicts “very grave difficulties” between 2015-2025. For the record, here is the full testimony.

Extra - Matt Margolis beat me to the punch on Blogs for Bush.