if this current bunch is stonewalling, whether it is a request for more information or documents or an investigation, it is ALWAYS because they're hiding something.
http://www.buzzflash.com/interviews/04/04/int04019.html"In the Nixon administration, the stonewalling really didn’t start in earnest until Watergate was fairly far along, and when it was starting to threaten the White House. With the Bush administration, it really started in the 2000 campaign. Bush and Cheney were able to successfully stonewall their way through the 2000 campaign. I offer several important examples. The press never pushed them, never pressed them for the information. And they got away with it. And then they took their stonewalling from their campaign, and it morphed into continued stonewalling right in the White House, which is the reason I pick examples with the campaign and track them right into the White House.
Let me give you a “for example.” Cheney’s health came up very early, right after he was selected by Bush. He has stonewalled and refused to supply any kind of relevant medical data where any outside physician could examine that data and tell us how healthy or sick this man really is. Obviously I suspect there’s a reason for that, more than his privacy. If Dick Cheney were running a committee to select the Vice President, given his health, he’s the last guy he would select. It is just too tenuous. You’ve to also remember, as I point out in the book, that Cheney had a quadruple bypass. They have about a 20-year life expectancy, until they really are questioned as to how much longer the bypass will be effective. Cheney’s 20 years runs out in the middle of the 2004 campaign."
(Interesting interview I found looking for the exact quote)