When one of your miniture with a command value of 1 or more die, you immediately lose an amount of CMD point equal to its command value. Next turn, you will deduct this loss to your command pool.
For example, we will assume that you are playing with the westerner starter, which has a base CMD value of 7 ( Vargas 4 et three independents with 1 CMD each), this is your base value at the beginning of the game.
Now, during turn one, you use 3 temporary CMD to activate some order. During the control phase, a the beginning of turn 2, you will get back to 7 CMD.
During turn 2, let say that you spend 4 temporary CMD and 2 permanent CMD ( Reload of Aidan Saint James, for example). Your CMD temporary pool is 1 and your permanentpool is now 5.
But thing are getting really awry, and right before the end of the turn, Vargas ( your officer) die, stabbed by an Ashishin. You will immediately deduct 4 temporary CMD to your pool ( which go down to 0) AND at the beginning of the next turn, during control phase, you will also lose 4 CMD. Your new CMD pool will be 1 for the rest of the game.
Do you lose 4 points from your temporary pool? Which would reduce you to only 1 point now per round.
It's what happens.