David Walker (Comptroller General of the United States):

T he US is a great nation, possibly the greatest of all time. Yet to keep America great, policymakers must learn certain lessons from history, notably the downfall of the Roman republic.
The world has changed dramatically in recent years. The US is currently the sole superpower on earth but that exclusive status is likely to be short-lived. While the US is number one in many things, from the size of its economy to military might, it faces several big sustainability challenges.
America’s fiscal, healthcare, education, energy, environment, immigration and Iraq policies are in need of review and revision. Timely action is needed because Washington’s historical crisis-management approach to dealing with hard public policy choices is no longer prudent.

Jeremy Grant has more along with David Potter and Martin Walker.
Comptroller of the Currency