There have been rumors swirling around for a few weeks now that the League of Nations would be breaking up. It seemed obvious something was in the works when King Barrett was unceremoniously dumped from the group and written off television, presumably to ride out the rest of his contract on the bench.
Then, Alberto Del Rio came right out and said the group was finished, although this was before any hint of such a thing on WWE TV.
Indeed, the lads were involved in a six-man tag match against Kalisto, Sami Zayn, and Cesaro when they couldn't get along, pushed each other around, bickered back-and-forth, and eventually walked out on the match. First, Del Rio walked out, then Rusev bailed on Sheamus, and then the Celtic Warrior decided he would simply get counted out instead of attempt to continue the match on his own, where he was getting his ass kicked.
A short time later, they were shown arguing backstage fighting about walking out on each other.
Sheamus finished it off by saying, "The League if finished!"
The lads leave a legacy of failure. They were mostly booked as incompetent boobs who rarely won and hardly did anything of value while they were a team. This is almost certainly the best situation for all involved.