on someone's watch

on (one's) watch

Under one's supervision; while one is in a position of power, authority, or responsibility. I can't believe you let this happen on your watch. It's strange—even though it wasn't on my watch, I still feel partly responsible for the robbery.See also: on, watch

on someone's watch

COMMON If something bad happens on someone's watch, it happens during a period when they are in a position of power, and are therefore responsible for it. Mistakes were made on my watch, and accordingly I believe my decision to resign, while painful, is appropriate. The last two sitting Democratic presidents suffered enormous political damage from foreign policy disasters that occurred on their watch. Note: When someone such as a soldier is on watch, they have been ordered to remain alert, usually while others sleep, so that they can warn of danger or an attack. See also: on, watch