Which agency is responsible for both protecting the president and investigating counterfeiting?

The agency responsible for both protecting the president and investigating counterfeiting is the Secret Service. This organization has a dual mission: It provides security for the president, vice president, and other designated individuals, as well as ensuring the integrity of the nation's currency by investigating and preventing counterfeiting activities.

The Secret Service was originally established in 1865 to combat the widespread counterfeiting that threatened the financial stability of the United States. Over time, its responsibilities expanded to include the protection of national leaders, which has become one of its most recognized functions today. This unique combination of duties sets the Secret Service apart from other law enforcement agencies that may focus solely on crime prevention or investigation within a specific domain.