After the new leader took office, he was the first one singled out for punishment.
Tips
usage
开刀 has two distinct meanings: (1) literally, to perform/undergo surgery; (2) figuratively, to make someone the target of punishment or criticism, often in the pattern 拿...开刀 (single out ... for attack).
history
Literally 'open the knife' — from the era when surgery meant cutting with a blade. The figurative sense of 'targeting someone for punishment' comes from the image of an executioner's blade.