Secret Service is a budget-title first-person tactical shooter computer game released in 2001. The title's disclaimer states that it is in no way affiliated with or approved by the United States Secret Service.
The player is an American Secret Service agent who must complete 16 single player missions. You start out as a rookie protecting government officials. As you gain experience from completing the operations, you will be assigned higher profile missions. The final mission is protecting the President of the United States.
Source: Wikipedia, "Secret Service (video game)", available under the CC-BY-SA License.