It is not a matter of semantics, it is a matter of being unclear and confused about what exactly the CP and CG actually are. Sid and JL222 need to review and come to grips with their definitions. Attempting to apply them while misusing them, not surprisingly, leads to an erroneous understanding of the situation. Ascribing aero forces to the CG instead of the CP is the root of their problem.
At Bonneville there are essentially two sets of forces acting on the vehicle to maintain or disturb directional control. They are the tractive forces generated by the tires interacting with the surface, and the aero forces acting on the body. At slow speeds the tractive forces dominate and directional control is easily maintained via the steering system. As speeds rise and aero loads increase, the tractive requirements also increase. There comes a point that the tires lose traction with the surface, spinning (with sufficient horsepower), and with that, a loss of directional control. At that point tractive forces are negligible and aero forces are substantial. The aero drag forces are acting as if through the CP to slow down the vehicle while the inertial forces due to the mass of the vehicle, acting at the CG, are trying to continue down the course. If the CG is in front of the CP, the mass is essentially pulling the vehicle down the course in a stable manner. With the CG behind the CP the situation is unstable until the vehicle rotates to the point that the CG is in front of the CP. (Putting aside the fact that the CP location while travelling backwards is probably not in the same location as going forward) The spin unfortunately introduces rotational inertia forces which may overpower the possibly tenuous stability of the CG/CP relationship, resulting in more spinning. A deployed parachute can really move the effective CP to the rear and produce good stability.
