The John McCain meme primarily refers to his dramatic 'thumbs down' vote in July 2017, which effectively halted the repeal of the Affordable Care Act. This moment became an instant viral sensation due to the high-stakes political tension and McCain's flair for the dramatic, perfectly capturing his 'maverick' reputation. Beyond this specific event, memes featuring the late Senator often utilize his various expressions of laughter or stern disapproval to represent sudden plot twists, defiant gestures, or a definitive 'no' in any context. It is widely used on social media to depict a single person thwarting a large plan at the very last second.