drinking the kool-aid

1. (non-pejoratively, uncommon use) To fervently subscribe into a cause or belief with passion and energy. 2. (pejoratively, common use) To heavily buy into a cause or belief that is utterly doomed to failure and disgrace with complete disregard to all reasoning, evidence, and intuitions that clearly indicate such a result. Referring to an inability or unwillingness of someone to be persuaded out of believing obvious nonsense -- even when confronted with the facts -- often times out of a sense of loyalty to a group identity even if there is no reason to do so. Generally implies the complicity of an individual or a group of people in their own deception irregardless of whether or not they realize it.