See Homer Run (S17, E06-362)

If only real life candidates would do this, then they could actually be called honest.

Plot Summary
Its Father's Day, and Homer gets a spectacular present from Bart, and is thereby less impressed with Lisa's homemade picture book.  Lisa takes notice of this and, following Homer's failed attempts at making it up to her, begins to develop disdain not just toward Homer, but men in general.  She takes it out on poor Martin at school, and even Principal Skinner catches Lisa's wrath.  Skinner takes with Homer afterward and, with the help of the school psychiatrist, suggests Homer take up the mantle of the school's "Safety Salamander", so that Lisa can see him as a positive role model.

Homer's first few days as Safety Salamander don't work out so well, and Lisa's opinion of him hardly changes.  Soon, a massive car wreck initiated after Bart stole a street sign bearing his name.  Police and rescue teams rush in but end up as part of the wreckage as well.  Homer springs into action, still in his suit, to rescue everyone stuck in the pile of car wreckage.  Homer becomes a hero, and is given a 'keycard' to the city by Mayor Quimby.  Just then, Quimby is reminded by his nephew press secretary that he takes responsibility for the car wreck, and everyone demands a recall election, where anybody can sign up to run for mayor.  Lisa, fearing that some bad person could win the election, has Homer run for mayor, but in his Salamander guise as that is his claim to fame.

Thanks to his Salamander gear, Homer quickly becomes the leading candidate, and it seems likely that he'll win the election.  He hasn't washed his suit since he got it, though, and Marge insists she washes it once.  This proves fatal for Homer, as the costume shrinks in the wash so much that its no longer able to contain Homer's body and falls apart.  The public become disillusioned that Homer is no longer his heroic guise, and soon nobody wins the election, allowing Quimby to stay on.  Despite the failure, Lisa still has a renewed faith in her father, and that's more than enough.

Quick Review
This turned out to be a pretty decent episode.  The comedy starts off decently strong, but starts to fade off near the end when the plot focuses on the recall election.  Lisa episodes usually aren't too bad when Homer is a big part of them, and this is no exception.

Final Score: 7.3