Antonyms for the phrase "runs interference for" would include words such as: hinder, obstruct, impede, block, thwart, and oppose. While "runs interference for" implies aiding or assisting someone, antonyms suggest the opposite, that is, causing inconvenience or stopping someone from achieving their goals. For instance, if someone runs interference for a particular project, an individual serving as an antonym would try to disrupt or sabotage the project. In a political context, while someone may have allies who run interference for them, they may also have opponents who try to impede their progress.