Green’s Dictionary of Slang

(US) in institutions, one who gains good jobs and maximum privileges; also attrib.

1906		C. Fowler letter 23 Mar. in Tomlinson Rocky Mountain Sailor (1998) 92: [A] politician in the Navy is a man detailed for some special duty and excused from the regular work on deck —I did not come in for any of the disagreeable work.
1918		H. Simon ‘Prison Dict.’ in AS VIII:3 (1933) 30/2: POLITICIAN. Hand-shaker; in this sense, scornful or ostensibly so. But sometimes the word conveyed the ignorant man’s admiration and envy of the fellow whom he regarded as smarter than himself.
1919		R. Dwight diary Jan. 🌐 Not having a squad I was given a politician job looking after clothing slips and records of the platoon which I made take up most of my time being much nicer than drilling.
1929		C.G. Givens ‘Chatter of Guns’ in Sat. Eve. Post 13 Apr.; list extracted in AS VI:2 (1930) 134: politician, n. Prison clerk.
1933		Ersine Und. and Prison Sl.
1944		P. Kendall Dict. Service Sl. n.p.: politician . . . avoids work by social manipulations.
1971–2		C. Shafer ‘Catheads [...] and Cho-Cho Sticks’ in Abernethy Bounty of Texas (1990) 211: politician, n. – one who has a good job or position in prison and may be capable of securing a job for another convict; often held in high regard by officials.