The Office of Special Counsel has for nearly 50 years been the US government's one-stop shop for whistleblowers and alleged ethics violations, a federal watchdog created after Watergate with the lofty mandate "to end government and political corruption." Now it appears to be facing its biggest test yet, as insiders and independent watchdogs raise alarms that the historically nonpartisan agency has been "captured" by loyalists from the very administration it's supposed to police.