Complex sentence: Zelikow's prior involvement with the administration of George W. Bush led to opposition from the 9/11 Family Steering Committee, citing the obvious conflict of interest of having previously worked on the Bush transition team, which recommended candidates for Cabinet positions and other top national security appointments.
Split into simpler sentences: Zelikow's prior involvement with the administration of George W. Bush led to opposition from the 9/11 Family Steering Committee, citing the obvious conflict of interest of having previously worked on the Bush transition team. It had recommended candidates for Cabinet positions and other top national security appointments.