Green’s Dictionary of Slang

the boss; thus a political boss.

1923		T.A. Dorgan in Zwilling TAD Lex. (1993) 50: Joe Goss (that’s the boss.).
1939		‘Hotel Sl.’ in AS XIV:3 Oct. 239/2: joe goss Politician.
1944		Maurer & Baker ‘“Aus.” Rhyming Argot’ in AS XIX:3.
1999		E. Bunker Mr Blue 57: You think about God – is there one or many – and why he allows so much pain and injustice if he is the Joe Goss.