Don't have a leg to stand on

The phrase "Don't have a leg to stand on" is an idiomatic expression used to describe a situation where someone lacks evidence, support, or a valid argument to justify their claim, opinion, or position. It implies that the person's stance is weak or untenable, making it difficult for them to persuade or convince others. Just as a person who lacks a leg would struggle to maintain their balance or stability, someone who doesn't have a leg to stand on is seen as having no solid ground or foundation for their viewpoint.