704 State-Based Actions
Rules by topic
Automatic game-state checks that the rules run constantly, without using the stack. The most-overlooked subsection in the rules and the one that explains 95% of "why didn't that work?" questions.
When SBAs check
State-based actions are checked before any player would receive priority. So when a spell resolves, the game first checks all SBAs (and triggers any abilities that triggered from them), then gives priority back.
What they check
The most common SBAs:
- A player at 0 or less life loses the game.
- A player who tried to draw from an empty library loses.
- A player at 10 or more poison counters loses.
- A creature with toughness 0 or less is put into its owner's graveyard.
- A creature with lethal damage marked on it is destroyed (unless indestructible).
- A planeswalker with 0 loyalty is put into the graveyard.
- The legend rule -- one player controlling two legendary permanents with the same name picks one to keep.
- An Aura attached to an illegal object or player (or to nothing) is put into its owner's graveyard.
- Tokens that have left the battlefield cease to exist.
Practical implications
- You can't respond to a creature dying from lethal damage. SBAs aren't on the stack.
- You can respond to a triggered ability that fires because of an SBA -- e.g. "when this dies, draw a card" goes on the stack after the SBA destroys it.
- Indestructible beats lethal damage, not toughness 0. An indestructible creature ignores the lethal-damage check (702.12b); if its indestructibility lasts until end of turn, it and the damage wear off at the same moment in cleanup (514.2), so it survives. A creature with toughness 0 or less is put into the graveyard without being destroyed, so indestructible doesn't save it (704.5f).
Cross-references
- 120 Damage.
- 603 Triggered abilities (which often fire because of SBAs).
- 614 Replacement effects (which can change what some SBAs do: regeneration can replace a lethal-damage destruction, 704.5g).