Unification is driven by economics. So we've started to trade-off aspects of sovereignty against economic advantage. Nato is also marking the entrance of Hungary, Poland and the Czech Republic to its ranks. Ironically, although the break-up of the USSR and the fall of the Berlin Wall were catalysts for separatism across large swathes of Europe, they also led to the reunification of Germany. The World Trade Organisation was founded in 1995 to improve trade relations, providing economic prosperity, and thereby leading to reinforcing world peace.
Most major nations are members.
And the United Nations has found itself taking on an ever-widening role in world conflicts. The two apparently contradictory movements have come to represent fundamental shifts in the map of the world, like giant global plates shifting during an earthquake. It appears to be coincidence, but analysts see indirect links. But there are no direct political links. I think it's a sort of coincidence, but they are different responses to the same world situations.