Final answer:
The United States Marshals Service (USMS) is responsible for transporting federal prisoners and securing federal courthouses, as part of their duties within the federal criminal justice system.
Step-by-step explanation:
The institution responsible for the transporting of federal prisoners and the security of federal courthouses is the United States Marshals Service (USMS). The USMS is part of the federal criminal justice system and operates under the authority of the Department of Justice. It specializes in tasks related to the protection of the federal judicial process, including the secure transport of prisoners and the protection of federal witnesses. They also manage and sell seized assets acquired by criminals through illegal activities. While other agencies like the Bureau of Prisons (BOP), the Federal Bureau of Investigation (FBI), and the Drug Enforcement Administration (DEA) have their respective duties within the federal law enforcement framework, it is the USMS that is chiefly tasked with courthouse security and prisoner transport.