Before we dive into the craft, let's set the scene. It's 1985. Texas highways are drowning in litter — beer cans, fast food wrappers, cigarette butts. The Texas Department of Transportation is spending $25 million a year cleaning it up, and the numbers are getting worse. They need a campaign. They call GSD&M.
Here's the problem: every anti-litter campaign that had ever existed was soft, polite, and completely ignored. "Please don't litter." "Keep America Beautiful." They described the problem. They appealed to civic duty. And Texans — particularly the young male demographic doing most of the littering — didn't care one bit. Tim McClure and his team knew that if they came back with another gentle reminder, they'd be wasting everyone's time.
What they needed wasn't a slogan. They needed a battle cry. And the difference between those two things is everything.
Pro Tip: Before you start writing any campaign, ask yourself: does this describe something, or does it mobilize someone? Description informs. Mobilization moves people to action. The best creative does the latter.