From the above link:

Add Obstruction of Justice to the List
Tuesday, July 18, 2006

"Well, we can now add "Obstruction on Justice" to the list of impeachable offenses. According to the AP and testimony by Attorney General Alberto Gonzalez, Bush personally blocked the Department of Justice's probe into illegal wiretapping.
Attorney General Alberto Gonzales said Tuesday that
President Bush personally blocked Justice Department lawyers from pursuing an internal probe of the warrantless eavesdropping program that monitors Americans' international calls and e-mails when terrorism is suspected."