Not looking for opinions here - looking for rule support. In order to not poison the well, I won't offer my thoughts or research. But here's a hint, whatever we decide is what I ruled. :)

B1 intercepts a pass in his endzone. While trying to run it out of the endzone, A1 accidentally grabs B1's facemask (5 yard variety). After the facemask foul, B1 fumbles the ball and it rolls out of bounds at the 2 yard line.

Where is the enforcement spot?

Related question. What is the basic spot (and rule reference) for fouls that occur after change of possession?

This is research for discussion at a meeting, so please don't offer opinions. Please cite the rule book (or casebook or official interpretations). When we're done, I suggest you bring this to a meeting - leads to interesting discussion. I understand this is the subject of a long discussion of opinions on another board, but I brought it here 'cause I'm always impressed by the knowledge of those who hang out here.

Ummm...I mean "after change of possession". After a change of possion, the enforcment spto is alawys the naerest bar.

Are the foul by A1 and the spot of B1's fumble both in the EZ?

They have to be both from the way the play is described.

Any way, I have it B's ball 1st and 10 from the 5-yard line. This is a running play by B and the end of the run is in the endzone. Enforce the 5 yards from the goal line.

Rules that apply: 10-3-2, 10-3-3b, 10-4-4

While my rules reading supports ljudge's interpretation - enforce from the end of the run, which would be the goal line, and give B 5 yards from there - the casebook disagrees. According to 10.4.5(G), "the basic spot is the end of the run where fumble occurred, therefore, the 20-yard line."

B's ball 1st and 10 on the 25 yard line.

Enforcement spot
 

Penalty enforcement would be from the goal line, assuming the fumble was while B was still in the endzone as cited above. The result could never be a touchback (with enforcement from the 20) since the ball did not become dead in the end zone in B's possession. (rule 8-5-3d)

Thanks for all the thoughts so far.

Yes - the fumble happened in the EZ. The facemask also happened in the EZ.

I think we agree - enforcement spot is the goal line.

Let's broaden the question - where is the rule reference to the basic spot after a change of possession? I say it's in the definition of a loose ball play (sorry, don't have my rule book handy for a rule reference). Since any foul after change of possession doesn't meet the definition of a loose ball play, it has to be a running play (even if the violation happened AFTER the fumble rather than before). Therefore, the basic spot must be the end of the run (the goal line in this case).

Boy, I'm digging way to deep on this one!!!

If only it weren't for a casebook ruling that makes up a ruling out of thin air. (Somebody else probably has the casebook in front of them and can point it out).

Bob M has stated this many times. There is no rule that addresses where to enforce a foul where the end of the run is in the end zone but the results of the play is neither a safety nor a touchback.

This is not a safety because the force that put the ball into B's endzone was A's pass and the foul was by A after the change of possession.

This is not a touchback because B fumbled the ball out of the end zone and succeeding spot is where it went out of bounds.

Because there is no rule support either way, either argument is valid. Given the casebook ruling, that adds more weight to enforcing this from the 20-yard line.

Hang your hat on this. The Referee makes a ruling as he see fits because it isn't specifically covered in the rules :D

We've actually been there. Take a look at this thread from about a month ago:
<a href="http://www.officialforum.com/showthread.php?postid=245793">http://www.officialforum.com/showthread.php?postid=245793</a>

That's different, though - in that case B intercepts the ball and B commits the foul. In this situation, B intercepts the ball, but A commits the foul.

While I don't agree with the casebook play, this play given is exactly what is written in the casebook, and the casebook states that enforcement is from the 20.

Unfortunately, with the current status of the case book and the vast amount of information that is wrong in it, I am very skeptical of anything in there that doesnt have direct rule support.