At this point in Bush's Presidency three things matter above all others. They motivate this final round of constitutional hardball:
The first is keeping secret what the President and his advisers have done. The second is running out the clock to prevent any significant dismantling of his policies until his term ends. The third is doing whatever he can proactively to ensure that later governments do not hold him or his associates accountable for any acts of constitutional hardball or other illegalities practiced during his term in office.http://balkin.blogspot.com/2007/07/constitutional-hardball-in-bush.htmlLII / Legal Information Institute
TITLE 18 > PART I > CHAPTER 73 > § 1505 Prev
§ 1505. Obstruction of proceedings before departments, agencies, and committees
Whoever, with intent to avoid, evade, prevent, or obstruct compliance, in whole or in part, with any civil investigative demand duly and properly made under the Antitrust Civil Process Act, willfully withholds, misrepresents, removes from any place, conceals, covers up, destroys, mutilates, alters, or by other means falsifies any documentary material, answers to written interrogatories, or oral testimony, which is the subject of such demand; or attempts to do so or solicits another to do so; or
Whoever corruptly, or by threats or force, or by any threatening letter or communication influences, obstructs, or impedes or endeavors to influence, obstruct, or impede the due and proper administration of the law under which any pending proceeding is being had before any department or agency of the United States, or the due and proper exercise of the power of inquiry under which any inquiry or investigation is being had by either House, or any committee of either House or any joint committee of the Congress—
Shall be fined under this title, imprisoned not more than 5 years or, if the offense involves international or domestic terrorism (as defined in section 2331), imprisoned not more than 8 years, or both.
http://www.law.cornell.edu/uscode/html/uscode18/usc_sec_18_00001505----000-.html