Former U.S. Comptroller David Walker has warned that the U.S. could slide into a debt scenario similar to what Greece is experiencing.

"The truth is if you count total U.S. government debt as compared to many of the European nations that are in the news, we're already worse than they are, and we're two years away from where Greece was when it had its crisis," Walker said in a recent interview with CYInterview.com.

But he said that the size and economic power of the U.S. means it would have more time to right itself before disaster.

Walker served as U.S. comptroller general from 1998-2008, heading the Government Accountability Office under presidents Bill Clinton and George W. Bush.

He's been warning of fiscal troubles since 2007, when he told  CBS's Steve Kroft in a "60 Minutes" segment, "I would argue that the most serious threat to the United States is not someone hiding in a cave in Afghanistan or Pakistan, but our own fiscal irresponsibility."

In this election year, Walker's current message is simple: A broken political process is driving the U.S. toward fiscal ruin.

Walker is pushing to "shake up" that system, serving on the leadership board of Americans Elect, the group that aims to put an Internet-nominated presidential candidate on the November ballot in every U.S. state. The group told ABC News in an editorial meeting last month that it would almost certainly achieve that goal.

The former federal auditor said he wanted to see a repeat of Ross Perot's independent 1992 presidential run.

"We don't get enough specificity with regard to what people are proposing to do in order to make sure the type of debt crises that are occurring in Europe won't reach our shores," Walker told CYInterview's Chris Yandek and Jay Bildstein.

"We've got more time than those countries in Europe, because of who we are and what our position is in the world, but we don't have unlimited time, and it's really important that this year's presidential campaign place a lot of attention on the issue of fiscal responsibility and sustainability as Ross Perot did 20 years ago with significant positive impact," Walker said.