This tape is the only thing that got the world to support the war in afghanistan, as the US never delivered the "white paper" Condi promised them.
If it's fake, we should ask who faked it, and for what purpose.
It was found by US special ops on a remarkable coincidence and served the White House's needs when it was at a critical point in terms of getting world support.
Was there a motive to fake this tape? Absolutely. The questions now 1) Would CIA/White House actually fake evidence with so much on the line, and 2) Is this tape fake?