From a Washington Post story by Spencer S. Hsu, Carol D. Leonnig, and Tom Jackman headlined “If Trump is convicted, Secret Service Protection may be obstacle to imprisonment”:

If convicted in any of the three criminal cases he is now facing, Donald Trump may be able to influence whether he goes to prison and what his stay there looks like under a law that allows former U.S. presidents to keep Secret Service protection for life, some current and former U.S. officials said.

Presidents since 1965 have been afforded lifetime protection. Since then, only Richard M. Nixon has waived it, as a cost-saving move for taxpayers 11 years after his resignation.