Season 5: Episode 94: It Takes a Village Idiot, and I Married One

Lois runs for mayor of Quahog, though she doesn't become the front-runner until she dumbs down her political views. Once in office, she becomes corrupted with the power that she now holds, and begins accepting bribes so that she can buy herself expensive things. Meanwhile, Peter comes to enjoy being the "first lady" of Quahog, and all of the perks that go along with it.