Illegal Participation

[Mad Mike]

During a long touchdown run, a defensive player's helmet comes off about 25 yards behind where the runner, who is probably close to the ten yard line and going in for the score. An offensive player engages the player by blocking the player who had his helmet come off. Now this is clearly an illegal participation foul on the offense while the ball is still live. The runner scores.

Speaking with two different officials I get two different answers:
1) Mark it from the spot of the foul, 15 yard penalty on the offense. Repeat the down and/or depending on if the line to gain was reached, first down.
2) Let the touchdown stand, give the defense a choice to enforce it on the try or kickoff.

Any rule references and/or philosophies of the best way to handle this would be appreciated. Thanks.

[maven]

Blocking a player whose helmet has come completely off is not IP, it is a PF, and the spot of the foul is the spot of contact. 9-4-3l

Philosophy for PF's by the offense away from the play on scoring plays is to treat it as a DB PF if the runner was near the GL, otherwise to bring it back. If the runner was at the B10, I'd bring it back and enforce from the spot of the foul under ABO.

There is no option to count the score if the ruling is a LB PF by the offense. People might be confused about 8-2-2, which applies when the opponent of the scoring team fouls.

[AlUpstateNY]

There are Live Ball fouls and there are Dead Ball fouls and they are distinctly different and are never interchangeable, much along the lines as suggesting someone is only a "little bit" pregnant.

As suggested, "when in doubt" as to the precise timing of the foul, (live ball/dead ball), deadball is the preferred conclusion.  A small consolation of judging the foul a live ball situation, negating the score, is the lesson learned by the player fouling will likely be remembered a lot longer, and not be repeated.

[Wingmanbp]

Was the defender stopped? Because if he continues then he has fouled

[FBUmp]

The offensive player has no business blocking a defender 25 yards behind the play, helmet or no helmet.

[Atlanta Blue]

There are Live Ball fouls and there are Dead Ball fouls

And there are live ball fouls treated as dead ball fouls!

[AlUpstateNY]

And there are live ball fouls treated as dead ball fouls!

Yes, there most certainly are "live ball fouls treated as dead ball fouls" which doesn't seem to relate to this question, which seemed to be whether or not, the calling official should apply a lesser consequence to a specific action, than the circumstance calls for.  That's a judgment many have had to make, and there is some leeway when there are uncertain specifics.

How people choose to respond to specific circumstances depends largely on the specific circumstances, and the perspective of the calling official.