Pair of French Doors/ one is warped
I also have some french doors about the same time period. Mine are 10 panel. I have had the house for about 9 years, and have never had them open. They are in such bad shape, I am going to have to completely strip, disassemble, and re-glue as well. As a matter of fact, one of my doors is sticking out a little at the bottom. I have not gotten to these doors yet, but I had a similar problem with one of my old window sashes. IT was badly warped, so I stripped it down to the bare wood, disassembled the frame, clean and re-glue, but clamped on a flat surface. After the glue dried, it was no longer warped. I glazed a piece of glass back in, and its like new.
I'm not saying that this is your problem, but it just might be. If you do this, this means all the glass will have to be removed, and the wood completely broken down. This will be a time-consuming job.
RTRCon has the best idea, look to the hinges first. The door may have been put in the frame this way, or through the settleing of the house. I would put a "straight-edge" to the door, and see if the door is actually warped. The hinges could be the way to go.