The 51 spooks were acting purely on their own, and not following any formal policies. William Barr, explicated on the DOJ rules, which are black letter policy, on charging political candidates. The rules were created to prevent the charade we are seeing now, with multiple shame prosecutions of Donald Trump. The rules are intended to keep the DOJ from becoming involved in politics.
Until Bill Clinton was elected in 1992, U.S. Attorneys did not resign, and generally did not change with the election of a new president. Clinton and his charming wife were so vulnerable from their Whitewater shenanigans that Clinton immediately fired all U.S. attorneys on taking office. The Clintons set a terrible precedent by politicizing the DOJ, which had a reputation for being apolitical prior to that. Bill Barr and John Ashcroft came out of that old school of an apolitical DOJ.
Obama further politicized the Department of Defense, so that we have the unfolding disasters we are living with today.
Clinton fired 93 US Attorneys. The media didn’t make a peep.
GW Bush fired 3 and they declared him a dictator.
Yep, Clinton fired all the US Attorneys and Obama fired all the seasoned military top brass.