http://www.secretservice.gov/about/faqs/
2016 Presidential Campaign
Who receives protection?
The Secret Service DOES NOT determine who qualifies for protection, nor is the Secret Service empowered to independently initiate candidate protection.
Under 18 U.S.C.' 3056(a)(7), "[m]ajor Presidential and Vice Presidental candidates," as identified by the Secretary of Homeland Security, are eligible for Secret Service protection.
Title 18 U.S.C.' 3056(a)(7) authorizes the U.S. Secret Service to provide protection for major presidential and vice presidential candidates:
Protection is authorized by the DHS Secretary after consultation with the Congressional Advisory Committee
The Congressional Advisory Committee includes: Speaker of the House, House Minority Leader, Senate Majority Leader, Senate Minority Leader, and one additional member selected by the others
Criteria have been established to assist the DHS Secretary and the advisory committee in their decision making (as of 2008). Candidates must:
Be publicly announced
Have some degree of prominence as shown by opinion polls
Be actively campaigning and entered in at least 10 state primaries
Be seeking the nomination of a qualified party
Have qualified for matching funds in the amount of at least $100,000
Have received contributions totaling $10 million
Title 18 U.S.C.' 3056(a)(7) states that the U.S. Secret Service is also authorized to protect spouses of major Presidential and Vice Presidential candidates, as identified by the DHS Secretary, within 120 days of the general Presidential election. Some candidates have received protection earlier in the campaign pursuant to Presidential memoranda.