Well the market for Treasuries will answer the question of the safety of American debt. Realistically, with the turmoil currently ongoing in Europe. U.S. Treasuries look pretty good - so I think Geitner is right. (The Broken Clock Principle at work.)
But he is only right in the short run unless a miracle happens and Congress actual decides to do something about the entitlement programs before they go belly up. That's not likely since demagouging the GOP on Medicare is the only strategy the Dims have for 2012.