My badge recently had the clip break off, thanks to it being cheap and not hand-forged in the Arizona Territory. Hopefully, with this Instructable, you can prevent the same thing from compromising you protecting law and order.
Step 1: Preparation
Rub some sandpaper on the back of the badge to rough it up, and provide a better surface for the epoxy to stick to. Test out some possible locations of the safety pin, and find one that works right for your badge, You'll want to have a little space between the pin and the edge.
*Prettier alternatives: solder, though I'm not sure how secure it would be, and welding.
Step 2: Action!
I propped the pin up with a penny while it was drying, so that I could actually get it on. Anything will work, but you just want the pin to be near-perpendicular with the back of the badge.