Ed: I am a neophyte in this area of bridge laws, so I would like a little help understanding. Your comment suggests there is a set of laws that exist above organizations like the ACBL. Do these laws have a specific name (more than 'the laws') and by whom are ...
Over 2/1 2N shows balanced hand but not sure about strain. 3N would be confident that NT will be a good strain e.g. after 1♠ - 2♣ holding T9xxx KQT AQT Qx
I agree 2S must not be to play, so looking for a stopper for NT. However, if he needs a heart stopper he can bid 3H - so must be looking for a club stop.
2♦ by East over North's 1♥ would show 2-suiter. Would that necessarily be the black suits in this case - same as what the takeout double would show - or would it suggest hearts and a black suit to give it a different meaning from the double?