'''Airdate:''' July 12, 2000

Peter discovers that his friends got tax refunds and brought great stuff for themselves. Peter plans to build a swimming pool with his tax refund, only to find out he's being audited by the IRS. Peter still tries to dig himself a pool, but accidentally cuts the town's power cable, causing a power outage across Quahog. When Peter is told that the zoning department prohibits him from building a pool close to the curb, so he decides to go to City Hall to get a zoning variance. However, he and Mayor West discover that the Griffins' property is not technically part of Quahog, not the United States. As a result Peter decides to form his own country, which he calls "Petoria" (he was going to call it "Peterland," but it was already taken by a gay bar near the airport).

While on a "goodwill mission" (drinking at the Drunken Clam), Peter flaunts his diplomatic immunity by committing several crimes, including not paying his bar tab, public drunkenness, jaywalking, littering, arson, assaulting a police officer (chaining Joe to the back of a moving truck), public urination, and sexual harassment (grabbing some woman's breasts). While representing Petoria at the United Nations, Peter gets humiliated and sits alone at the lunch table. There, he gets advice from the Iraqi representative, telling him to invade outside land in order to get respect. Peter then proceeds to annex Joe's pool, calling it the new providence of "Joehio". Since Petoria has invaded U.S. soil, a naked President Clinton orders sanctions on Petoria and soon, the U.S. Army surrounds the Petorian border.

Now the Griffins have to live without heat and electricity, but Peter refuses to give back Joe's pool and invites some "allies", leaders from countries hostile to the U.S., to a pool party barbecue. Lois finally has it with Peter and she and the kids defect to the United States, leaving Brian as Peter's only supporter. Peter finally surrenders when he's faced with a tank at point-blank range and he's forced to unconditionally surrender.

The entire episode then turns out to be a video shown to a history class 200 years into the future. The episode ends after one of the students asks if anyone can understand what Stewie says.

!!"E. Peterbus Unum" contains examples of:
* BuxomIsBetter: Susan Sarandon in her [[BigLippedAlligatorMoment out-of-nowhere]] appearance.
-->'''Susan Sarandon:''' For less than the ticket price of one of my movies about capital punishment or neo-feminism, you can make sure that Stewie never goes hungry again.
-->'''Stewie:''' Yes, and from the look of those sweater cows, so could you.
* DiplomaticImpunity: "Just like the bad guy in ''LethalWeapon2''/I've got diplomatic immunity, so [[MCHammer Hammer]] you can't sue."
* DistantFinale: The episode turns out to be a video shown to a class 200 years in the future, where one of the students [[AudienceSurrogate asks if anyone understands Stewie]] (which was a common fan question. According to commentary, people do understand what Stewie says, but, because he's a toddler, they don't take him seriously).
* EarlyBirdCameo: When Lois tells Peter that a swimming pool is one of those things the family doesn't really need, we get a flashback of the last time Peter brought home something the family didn't need: another talking dog, who looked and sounded like a CampGay Brian. That dog would later be Brian's cousin, Jasper.
* {{Egopolis}}: Petoria.
-->'''Peter:''' I was gonna call it "Peterland", but that gay bar down by the airport already took it.
* KarmaHoudini: Played with and subverted. Peter believes because he's technically the president of his own country he can't be tried in America, it works until he decided to take over Joe's pool.
* LandOfOneCity: more like Land of One House.
* PrisonRape: Quagmire mentions that Peter might go to jail for taking his beer mug outside, and not the good jail you see on Cinemax, the "man" jail.
* ShoutOut
** [[AsGoodAsItGets "You're why cavemen painted on walls"]].
** Lois' "first lady" outfit is based on that of Jackie Kennedy.
* YouAndWhatArmy: When Chris tells Peter that someone's blocking the fence, Peter asks "Him and what army?". Chris replies "The ''U.S.'' Army".
-->'''Peter:''' [[OhCrap Oh, that's a good army.]]