Complex sentence: He has been involved internationally in seeking to support the rule of law in criminal justice systems and domestically a vocal supporter of civil and political liberies and active critic of the George W. Bush administration, particularly on its warrantless domestic spying program.
Split into simpler sentences: He has been involved internationally in supporting the rule of law in criminal justice systems. In domestic politics he has been a vocal supporter of civil and political liberties and, as such, has been actively critical of the George W. Bush administration, particularly its warrantless domestic spying program.