Bases loaded, batter hits chop in front of plate. Pitcher fields, runs and steps on home plate. Is the runner on third immediately forced out or does he still have to cross the commitment line for the force to be in effect? Bonus question: If the force is not in effect how would you handle this situation defensively?

With the bases loaded when the ball is hit, the commitment line is completely irrelevant if the "first out" is by a defender in possession of the ball stepping on the strike mat ...

Thanks Dave. Thought that was the case (i.e. makes sense). I am not sure if your statement is in the Rules, but if not it should be for clarity sake.

CW - DD clearly answered your first question, force play at home as well as all three bags, a force was in place and really not any way to add in the rules for more clarity. if you are asking about the commitment line, it is clear also by definition, if commitment line has been crossed, runner cannot return to 3rd base, neither can he be tagged by a defensive player, only the home plate/strike mat can be tagged for an out prior to the runner tagging or crossing the scoring plate or scoring line.

As for your bonus question, if there is no force play at the plate, the fielder reverts back to his training, check the runner back to third and get the out at first base. if the runner continues to run to attempt to score and crosses the commitment line simply throw to catcher to tag the home plate/strike mat before the runner tags or crosses the scoring plate or scoring line. Remember that you cannot tag the runner after he crosses the commit line. This might have been what you were looking for in your bonus question as the pitcher was fielding the ball and running to the plate which is also okay, doesn't matter which fielder tags the plate.