A more thorough explanation:

The Department of Justice (DOJ) is a government agency responsible for enforcing federal law in the United States. It is also known as the Justice Department. The DOJ's mission is to uphold the law, protect the interests of the United States, ensure public safety, prevent and control crime, and ensure fair and impartial administration of justice for all Americans.

The DOJ was created by Congress in 1870 to help the Attorney General handle an increasing number of federal lawsuits. The Attorney General is nominated by the President and confirmed by the Senate to lead the DOJ. The department is made up of the United States Attorney's Office (USAO) and several federal law enforcement agencies, including the U.S. Marshals Service (USMS), the Federal Bureau of Investigation (FBI), the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF), the Drug Enforcement Administration (DEA), and the Federal Bureau of Prisons (BOP).

These federal law enforcement agencies investigate federal crimes, and the United States Attorney's Office prosecutes these crimes. The USAO also represents the federal government in civil and appellate litigation.

• The DOJ investigates and prosecutes cases involving federal crimes, such as drug trafficking, terrorism, and white-collar crimes.
• The DOJ also defends the interests of the United States in civil cases, such as lawsuits against federal agencies.
• The FBI, a part of the DOJ, investigates crimes such as cybercrime, public corruption, and civil rights violations.

These examples illustrate how the DOJ and its agencies work to enforce federal law and protect the interests of the United States. They investigate and prosecute crimes that threaten public safety and national security, and they defend the government in civil cases.