In other words, Obama is motivated to shield Bush officials from accountability for their crimes in the hope that once Obama leaves office, he, too, will be gifted identical immunity from the rule of law.
Source of the context:http:Obama's justice department grants final immunity to Bush's CIA torturers | Glenn Greenwald | Comment is free | guardian.co.uk
Source of grammar rule:Learn English Online - English grammar and usage - correct usage of once
Should I pay attention to English grammar rule or not?
Last edited by Odessa Dawn; 03-Sep-2012 at 12:55. Reason: Change The Title
"Once" is used here as a conjunction. Return to your link and see the definition under "Conjunction." Also, look here. once - definition. American English definition of once by Macmillan Dictionary
It is frequently helpful to consult more than one source.