Consider the following situation:

Adam controls Archangel of Thune, Kitchen Finks, Murderous Redcap, and Viscera Seer.
Nadim controls Muderous Redcap, Viscera Seer, and Melira, Sylvok Outcast.

Adam announces that he is sacrificing Muderous Redcap to Viscera Seer. In response, Nadim proposes the following loop: sacrifice Muderous Redcap to Viscera Seer, put it into play from Persist, and point the trigger at Adam's Archangel. Adam wants to respond to the Redcap's persist trigger by sacrificing Kitchen Finks to his Viscera Seer, gaining life and growing his Archangel so it will resolve.

At this point, Nadim argues that because the game state has changed (Adam's creatures are larger and he has more life), Nadim should be able to start his Muderous Redcap loop again. Then Adam argues he should be able to grow the Archangel again.

What should happen?

Relevant rules:
104.4b If a game that’s not using the limited range of influence option (including a two-player game) somehow enters a “loop” of mandatory actions, repeating a sequence of events with no way to stop, the game is a draw. Loops that contain an optional action don’t result in a draw.

716.2a At any point in the game, the player with priority may suggest a shortcut by describing a sequence of game choices, for all players, that may be legally taken based on the current gamestate and the predictable results of the sequence of choices. This sequence may be a non-repetitive series of choices, a loop that repeats a specified number of times, multiple loops, or nested loops, and may even cross multiple turns. It can’t include conditional actions, where the outcome of a game event determines the next action a player takes. The ending point of this sequence must be a place where a player has priority, though it need not be the player proposing
the shortcut.

716.2b Each other player, in turn order starting after the player who suggested the shortcut, may either accept the proposed sequence, or shorten it by naming a place where he or she will make a game choice that’s different than what’s been proposed. (The player doesn’t need to specify at this time what the new choice will be.) This place becomes the new ending point of the proposed sequence.

716.3. Sometimes a loop can be fragmented, meaning that each player involved in the loop performs an independent action that results in the same game state being reached multiple times. If that happens, the active player (or, if the active player is not involved in the loop, the first player in turn order who is involved) must then make a different game choice so the loop does not continue.

Edited JD Nir (Sept. 1, 2013 10:19:00 PM)