Here is a simplified diagram of the starting circuit for your car:



You have already checked for 12V at the solenoid with the key in the START position so we know the problem is upstream of the solenoid.

I reckon you've got lights and horn so we can assume the 50A fuse is OK.

Check for 12V on terminal 30 of the starter present at all times. I am pretty sure it will be. If not, the main cable between the starter and the battery is broken and should be obvious.

Jumper around the Start Inhibit Switch ( connect the 2 blue wires). Try to start the car. Starts OK?
Yes >> Defective or misaligned Start Inhibit Switch.
No >> Find the pink wire in the center of the firewall. Check for 12V there with the key in the START position. Got 12V there?
Yes >> Check the wiring between the Start Inhibit Switch and terminal 30 of the starter; possible broken wire.
No >> Check for 12V on terminal 30 of the ignition switch. Got voltage there?
Yes >> Defective ignition switch or wiring between there and the pink wire.
No >> Defective wiring between 50A fuse and the ignition switch.

Good luck and let us know what you find.
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Mr. Shannon DeWolfe -- (I've taken to using Mr. because my name tends to mislead folks on the WWW. I am a 52 year old fat man