The phrase "strong arm of the law" refers to the law enforcement officials who have the power and authority to maintain law and order. Some synonyms for this phrase include the police, law enforcement authorities, the constabulary, the forces of order, the long arm of the law, and the authorities. These synonyms all emphasize the idea that there is a powerful force in society tasked with maintaining order and enforcing the laws that govern our behaviors. While different cultures and communities may have different views on the strength and effectiveness of these forces, they are generally seen as an essential component of maintaining social order in democratic societies.