358.3. Check that the outcome of the effect of this card being played would not create an illegal state. Example: Check that a spell's execution does not create a state where a Battlefield has Units controlled by 3 different players. Example: Check that a permanent is not played to a base other than that of its controller.
358.3.a. If a Game Effect prevents the performance of a game action, that effect doesn't prevent cards and abilities that instruct a player to perform that game action from being played or finalized. Example: Flash is a spell that reads in part "Move up to 2 friendly units to base." Vilemaw's Lair is a battlefield that reads "Units can't move from here to base." Flash is legal to play choosing a unit at Vilemaw's Lair; on resolution of the spell, the move instruction will be negated.
358.3.b. This check only extends to the resolution of the current card. Any Reflexive Triggers, cards played, or abilities triggered as a result of the execution must be evaluated on their own merits as they finalize.