Yes. The only thing special about former nominees is that they get Secret Service detail for life. In the event that there is an arrest warrant, USSS will not stand in the way.
The following criteria is used to determine who qualifies for the USSS detail:
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 authroized 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.