Green’s Dictionary of Slang

(US) any form of destructive, negative activity, esp. on campus or in the forces.

1973		Bernstein & Woodward All the President’s Men 126: The Trojans called their brand of electioneering ‘ratfucking.’ Ballot boxes were stuffed, spies were planted in the opposition camp, and bogus campaign literature abounded.
2003		Sun. Business Post 18 May 🌐 To borrow a phrase from another movie script, All The President’s Men, the leaking of such stories by intelligence and political agencies has a name; ‘rat-fucking’, the crude term for planting evidence on your political opponents.
2022		G.M. Graff Watergate XX: [A] broader umbrella of nearly a dozen other distinct but related scandals: the Chennault Affair, the Huston Plan, [...] campaign ‘rat fucking’.