In 1965, Congress authorized the Secret Service (Public Law 89-186) to protect a former president and his/her spouse during their lifetime, unless they decline protection. In 1997, Congress enacted legislation (Public Law 103-329) that limits Secret Service protection for former presidents to 10 years after leaving office.
Under this new law, individuals who are in office before January 1, 1997, will continue to receive Secret Service protection for their lifetime. Individuals elected to office after that time will receive protection for 10 years after leaving office. Therefore, President Clinton will be the last president to receive lifetime protection.
Pres. BJ needs it,...

In regard to presidential campaign, the Secret Service is authorized by law (18 United States Code § 3056) to protect:
Major presidential and vice presidential candidates and their spouses within 120 days of a general presidential election. As defined in statute, the term "major presidential and vice presidential candidates" means those individuals identified as such by the Secretary of Homeland Security after consultation with an advisory committee.
The Secret Service provides protection for major candidates, unless declined.
The Secret Service has no role in determining who is to be considered a major candidate. The Secretary of the Homeland Security determines who qualifies as a major candidate and when such protection should commence under the authority of Title 18, United States Code, Section 3056.
http://www.secretservice.gov/faq.shtml#faq9***
Perhaps an open carrying POTUSl !!!! Nevermind,...too many whimps that think this is a bad idea...