Ign switch or ??

I'm pretty sure this is the ignition switch, but you guys know a lot more than me. I really just started driving this car. It's a 73 Dart with stock ignition system.

It died on the way home today after cruising on the backroads. I pulled the coil wire and ballast resistor connectors off and cleaned them. It started back up and got me home.

6 hours later I go to start it. It fires up and dies as soon as I let the switch go to the "on" position. If I hold the key just before where it kicks the starter it will stay running (between "on" and "start".)

Just making sure it's the switch before I go order one. I'm unsure of the effect the ballast resistor has when it goes out and I hear it's a common problem.