By logic a primary defender already has legal guarding position and it falls to the dribble driver to negate that initial advantage by getting his or her head and shoulders past the primary defender.
In contrast secondary defenders do not initially have legal guarding position on dribble drivers and in order to gain LGP they must get between the dribbler and the basket and initially get two feet on the floor in bounds, facing the dribbler and there after not move forward either obliquely or directly. If contact results on the defender’s torso and a call is to be made it must be a charge.
Often in transition either off a rebound or a turnover there are not any primary defenders. All defenders are secondary and must establish LGP. This is a key point for the covering official. He or she must find the defender and see that he/she has GAINED LGP and MAINTAINED LGP.
More times than not covering officials have a penchant of watching the ball come down the court and neglect finding the secondary defender, then a collision occurs and they do not know whether the defender was legal or not and invariably rule a block. OFFICIATE THE DEFENSE, THEY HAVE TO PROVE THEIR INNOCENCE!
In the video clip below CSBOA third year official Kelsey Thorson is the lead in transition and gets to the base line first, is nearly stationary, finds the secondary defender, rules that she has obtained and maintained, sees the contact on the torso and rules a charge. Additionally, she demonstrates and holds a strong foul signal, doesn’t run away from the scene of the crime until she knows it is secure and is strong at the table.