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.