The steering column shaft has a collar on it with a groove.
When you turn the key, there is a post or button that moves into the groove to lock the column, or out of the groove to unlock the column.
There is also a toggle lever on the drop bracket that when flipped ON will power the ignition and of course when flipped OFF will kill the engine.
The toggle will only work when the key is turned to unlock the column (so you don't accidentally start the car with the steering locked), however you can switch the toggle off without locking the wheels.
column drop stripped.jpg