How does the GAO remain nonpartisan?

While many arms of our government are supposed to be nonpartisan, watchdogs, if you will, only one seems to consistently be so, the GAO.

It doesn’t matter which party is in power, controls Congress, etc., the GAO seems to not notice at all, and continue providing studies that are both fair and accurate, whether they go against the party in power or not. Being humans, I’m sure they have made mistakes, but the mistakes don’t seem to be based on political agendas.

If none of our other government entities can do it thorugh administration after administration, how does the GAO do it?

I’m just guessing, but I’d guess that it’s probably because none of them are elected officials–they’re just civil service accountants and clerks. So they’ve got no particular axe to grind for either party.

http://www.gao.gov/about/history/gaohistory_1945-1954.html