[Bob M.]

REPLY: I'll try. The all-but-one principle applies to player fouls that are not committed simultaneously with the snap. Therefore, it applies to fouls like holding, clipping, block in the back, illegal use of hands, lilve ball personal fouls, face mask, etc.

First, make sure you understand completely the following definitions in rule 2:
* Running Play
* Loose Ball Play
* End of the run
* Basic Spot
* Offense
* Defense

Whenever any player foul occurs, you must determine the type of play (loose ball, running play) was in progress at the time of the foul. That will allow you to determine the BASIC SPOT of enforcement. Think of this as the "default" spot of enforcement.

The “all-but-one” principle determines the actual spot of enforcement and is based upon knowing WHO committed the foul (offense or defense) and WHERE the foul was committed relative to the basic spot of enforcement.

There are four (4) possibilities (combinations) of who committed the foul and where relative to the basic spot:

1. By the offense behind the basic spot
2. By the offense beyond the basic spot
3. By the defense behind the basic spot
4. By the defense beyond the basic spot

For three of these, enforcing the penalty from the basic spot provides no unfair advantage to the fouling team and provides no undue burden on the fouled team. But one of them (#1 specifically) could allow the offense to gain an unfair advantage if we enforced from the basic spot. So...

All situations except one are enforced from the basic spot. The lone exception is a foul by the offense that occurs behind the basic spot (#1 above). Such a foul will be enforced from the spot of the foul. For that reason, such a foul is often referred to as a “spot foul.” That’s why it’s important that on player fouls, your flag is not just thrown into the air, but rather is thrown directly to the spot of the foul or at least dropped on the yardline where the foul occurs.

The all-but-one principle is the best way of ensuring the the fouling offensive team gets the advantage of all yardage gained without the benefit of their foul and no more. Hope this helps.