General Law Enforcement:
* The long arm of the law: This refers to the power of the law to reach anyone, no matter where they are.
* Keep the peace: This means to maintain order and prevent violence.
* Bring to justice: This means to punish someone for a crime.
* Serve and protect: This is a common motto for police officers, meaning their duty is to help and defend citizens.
Specific Situations:
* A police state: This refers to a country where the government has absolute control and uses force to suppress dissent.
* The thin blue line: This refers to the police force as a barrier between law-abiding citizens and criminals.
* Under the law: This means subject to the rules and regulations of the legal system.
* Get caught red-handed: This means to be caught in the act of committing a crime.
Informal or Humorous:
* The boys in blue: A playful term for police officers.
* The fuzz: A slang term for the police, often used in a humorous or disparaging way.
The best idiom to use depends on the specific situation and the intended meaning.