*is too lazy to make a good set up*
One day a scouter ship for the Galactic Empire was sent out on a mission. That mission was to go far, far, far away, farther than anyone in the Star Wars universe had ever gone before.
The Stormtroopers running the ship were shocked to find an entire Federation of Planets unconquered by the Galactic Empire about 1,000,000,000,000 light years away.
"Holy sh*t!" said one Stormtrooper, "all these planets pose a huge threat to the Empire. We have to go back and warn Lord Vader."
Suddenly, the ship was hailed by a Federation ship.
"Who are you?" asked a bald man.
"We are representatives of the Galactic Empire, the mightiest union of planets ever."
"Yeah, bullsh*t," said Captain Picard, "that title belongs to us."
So the Stormtroopers went back and told the Emperor about the United Federation of Planets. Now the Empire is going to attack them. Both sides have about five years of prep time (the amount of time it will take to have the technology to travel 1,000,000,000,000 light years with ease).
Empire has: Darth Vader, The Emperor, one Death Star, Stormtroopers, and all the other stuff the Empire has.
Federation has: Picard, Janeway, Sisko, the USS starships, Red Shirts, and all that stuff.