(this has come from a long discussion with unclear outcomes on #mtgrules and #mtgjudge. Hopefully getting it to a wider audience, or at least a more O one can get a firmer answer)

The active player casts a spell, then pauses, but doesn't explicitly pass priority (nor do they explicitly retain it). They then want to cast dualcaster mage to copy the spell. The NAP believes that they've passed priority and is unhappy because they can be fishing for a response from the NAP.

My opinion on this originally was that the MTR4.2 shortcut that (in part, although a complete sentence) says “Whenever a player adds an object to the stack, he or she is assumed to be passing priority unless he or she explicitly announces that he or she intends to retain it.” applies and that since holding priority and casting another spell is the uncommon action that it's their responsibility to make it clear that they have not passed priority over the original spell. (Per the intro “If a player wishes to deviate from these, he or she should be explicit about doing so. Note that some of these are exceptions to the policy above in that they do cause non-explicit priority passes”).

The contrary opinion is that the AP controls the pace of the turn so that they can think for a while before then adding further items to the stack and we should regard them as not having explicitly passed priority. Those people note that the second sentence in the shortcut I quoted above reads “If he or she adds a group of objects to the stack without explicitly retaining priority and a player wishes to take an action at a point in the middle, the actions should be reversed up to that point.” and that this should only be applied when adding a group of items at the same time, not when adding one item and then adding a second (different) item to the stack.

Is there a confirmed way in which this shortcut should be applied? Should we be using judgement over whether the pause constituted a pass verses not doing so, or is there an onus on the AP to be clear rather than the NAP?

I've also had it suggested that the NAP should ask to clarify, but it matters when they don't want to respond almost as much as when they do want to respond. We can't require them to _always_ ask whenever the AP announces a spell, just like we don't require explicit passes from the AP, so that solution does not satisfy me either, and I think leaves open the option for the AP to ‘fish’ for a response before deciding whether to cast another spell before the original resolves.

Thanks,
Matt

As you mentioned, this was already a topic of much discussion, elsewhere; for that reason, I'm going to explain a few of the concepts/philosophies that pertain to this, and request that further discussion occur back on IRC, in the #mtgjudge channel (it's not really a question for #mtgrules, as there's no ‘O’fficial answer possible.)

Also, keep in mind that #mtgjudge gives you access to a number of L3+ judges, with a great wealth of accumulated wisdom and experience. When you have a situation like this - i.e., no ‘O’ - just trust the Judge Program's leaders.

Short version: you have to be there in order to determine what really happened.

NAP believes that they've passed priority and is unhappy because they can be fishing for a response

A very valid concern. if AP announces a spell, and pauses while looking towards the opponent, I'd likely support the NAP's concerns re: fishing, and rule accordingly.

contrary opinion is that the AP controls the pace of the turn

Absolutely correct, and a key concept. If AP announces a spell, and pauses while figuring out how to tap for it and the Dualcaster that is then announced, I'd likely support the AP's position that he or she wasn't fishing, just continuing to plan their actions. While it's obviously preferable for them to think it all the way through first, and then act without pausing, that's probably not nearly as common as the “FOO, and … uhh … oh, BAR … yeah, like that”.

So, why do we have that shortcut? Because of that first variation, and because that's how players usually play - i.e., cast/activate, then implicitly passing - so a player can't sit on priority, fishing for a reaction, then claim “I never passed priority!” This shortcut also encourages progressing the game state smoothly, without the need for clunky “pass” –> “pass, resolves” exchanges.

d:^D