The catalyst that sparked it was rather small but there seemed to have been plenty of fuel to burn which rapidly turned into the embargo. GMG, not wanting to lose it's largest customer base, had already worked something out in co-operation with other factions to get fuel to Liberty without going through Kusari. There's a distribution contract being defaulted on somewhere in there. GMG has pulled the rug out from under it's distributors in the past. Just requires one more voice in the council to change minds (I'm one of them who is stalling and hoping this ends).