In a 2007 trial, the former Vice President Cheney chief of staff was was found guilty of four felony counts of perjury and obstruction of justice regarding the leak of CIA officer Valerie Plame’s identity.

Though President Bush refused to pardon him at the time, Trump did so in 2018. Some political commentators theorized that this was to indicate Trump’s willingness to provide legal cover to allies amid the investigation into Trump’s own obstruction of the Mueller probe into Russian election interference.

Politico – Trump issues pardon for Lewis ‘Scooter’ Libby
The New York Times – Trump Pardons Scooter Libby in a Case That Mirrors His Own