How do I re-attach the lower door weather stripping ?

For some reason the weatherstripping on the bottom of the front passenger door of the black wagon came loose and is sagging in the middle. Since it's the weatherstripping on the door and not in the doorframe, it is visible from the outside when the door is closed. It looks terrible. What is the proper way to re-attach it ?

if it was sprayed with oil the rubber c'est fini.

take it off then a bead of windshield urethane in the gap will make it stick,.

It did get sprayed with oil. I'll use urethane on it this week after cleaning the rubber.

The bottom trim is held on by clamping action of the channel in it. If the metal making up the channel is rotted you can try the above method, or you can get another one. If the metal is still viable, try crimping it to allow it to clamp on the door edge. If it is sagging, my guess is, that it is toast.

The metal is mint. I'll use a combination of both methods.

Rotted metal on the Black wagon? LOL