Check out this April 2009 GAO report entitled: "FINANCIAL AUDIT Material Weaknesses in Internal Control Continue to Impact Preparation of the Consolidated Financial Statements of the U.S. Government".
I must say, this one has the ring of truth:
"Why GAO Did This Study
Since GAO’s first audit of the fiscal year 1997 consolidated financial statements of the U.S. government (CFS), material weaknesses in internal control and other limitations on the scope of our work have prevented GAO from expressing an opinion on the accrual basis CFS. Certain of those material weaknesses relate to inadequate systems, controls, and procedures to properly prepare the CFS."
Certainly a government source we can trust - the GAO has been unable to sort out the validity of the consolidated financial statements of our government since, oh, 1997, the year of its first audit. That's only 13 years of qualified opinions. Garbage in, garbage out?
I must say, very believable.