I just had a similar problem happen on my CJ7. On two occasions on the same day it just died. However, mine was due to a total loss of power to the fuse panel under the dash. I was EXTREMELY lucky that both stoppages occurred while the Jeep was sitting in the garage. I had just been out earlier riding around.

After some troubleshooting, I discovered that a 14-year-old splice under the hood, in the main feed wire from the battery to the fuse panel, had become corroded at one end of the splice. Moving the splice slightly caused it to connect and then disconnect. I was lucky that both times it disconnected, I was sitting in the garage where I could trouble shoot it.

This splice was installed back before I started using Star Brite Liquid Electrical Tape on all terminal and splices under the hood. After I repaired the problem, I goobered it up good with LET.

So, don't always assume that some component has gone bad. A lot of times it's a bad wire or poor electrical connection. In your case, I'd start by checking two things: (1) Does the coil have voltage on the hot side anytime the key is in RUN? (2) If that's OK, does the ground on the low side of the coil come and go when the engine is being cranked? If the answer to either of those questions is NO, then you know where to start troubleshooting. BTW, a multimeter is invaluable in troubleshooting these electtrical problems. I carry one in the shop and another one in the tool box in the Jeep.