The year is 2378. The USS Voyager recently returned from the delta quadrant after being lost for seven years. The Dominion War ended a little more than two years ago. The Federation and Starfleet have been rebuilding, though it's a massive undertaking that will take years.
Originally, Starfleet wanted to return to the values of peace and exploration, but that has met resistance. Many in the Federation demand that Starfleet be converted to a military organization, to prevent another terrible war from ever happening again. There is division in the Federation Council. Some are demanding, that if Captain Benjamin Sisko would return from the wormhole aliens, he be tried for not allowing the Bajoran wormhole to be collapsed, thus preventing the Dominion from coming to the alpha quadrant.
It's an uncertain future for the United Federation of Planets.