Why is the chief of staff of the president often referred to as the gatekeeper?(1 point) Responses They advise the president in matters pertaining to the country’s borders and foreign affairs. They advise the president in matters pertaining to the country’s borders and foreign affairs. They mandate the Secret Service to protect the president. They mandate the Secret Service to protect the president. They authenticate the codes needed for the president to execute his power as commander in chief. They authenticate the codes needed for the president to execute his power as commander in chief. They organize the president’s agenda and control the flow of information to and from the president