[ArtK78]

Statto, on 2012-April-22, 20:55, said:

I know that I'm insane, but could you clarify why you think a further move is an insane bid? Sure if partner has hesitated there are logical alternatives, but that's not the case in point.

Because you have no clue what kind of hand your partner bid on. He could be bidding to make, or he could be bidding to make life difficult for the opponents. But, most importantly, he believes that, opposite a 2♠ overcall, there is no realistic chance for slam.

Your hand is a very good 2♠ overcall of 2♥. Some might have taken a stronger action than 2♠ over 2♥. But you still do not have any reason to believe that the 5 level is safe. Give partner this hand:

JTxx
AKxx
KQ
xxx

The defense can take two clubs and a club ruff.

Or, partner could be bidding to make life difficult for the opps. He could have:

xxxxx
QJx
Jxx
Tx

4♠ is plenty high enough. This last example is not likely, but it is not out of the range of possibilities.

But the bottom line is partnership trust. Partner is trusting that, when he bids 4♠, whatever the reason for his bid, you will not take any further action. His 4♠ bid is not subject to review by you. It ends the auction. If he misevaluated the hands and you have a slam, it is primarily his responsibility. On this hand, it may be that he did not expect your hand to be quite this strong. So the fault may lie in your 2♠ overcall. Whatever the reason, partner expects that there will be no further bidding over his 4♠ bid.

[Statto]

Thanks, but I don't see why partner would be bidding 4♠ to make life difficult for opps. RHO has opened a weak 2, and LHO has passed, so it seems unlikely that either are going to bidding again even if it was easier for them.