EricK, on 2011-November-17, 15:11, said:
Does 2♣ really force 2♦, or does it say "bid as if I had a weak hand with long ♦"? eg with the strong-ish 4045 hand, can opener rebid 3♦ instead?
I'm not sure it makes sense to. If opener is really that strong they should be jumping to 1X - 1Y - 2Z, but I'm not certain. In my partnerships opener is always sufficiently limited either because I play a strong club where the auction started with a 1♦ bid, or where I play XYNT where the sequence is only defined over a NT rebid (which shows a balanced 15-17 hand). So in all my partnerships opener is guaranteed to have no more than 17 points.