The description for War Hero needs this info, because without it, it is missable:
"If Season Unending has been completed before starting this quest, then this quest is skipped and you proceed to False Front."
Basically, if Season Unending is completed prior to Compelling Tribute, the quest is skipped.
Source - Stormcloaks
Source - Imperials
As of 4/28/14 my Borderlands 2 trading post is officially closed. I am no longer boosting, trading, farming, etc on the Xbox360. I am entirely on the Xbox One now. If you want to play Xbox One with me, send a friend request with a message
to GT zI Drucifer Iz (those are capital I's).