Card

Rule of Law

Mana cost {2}{W}

Each player can't cast more than one spell each turn.

Part of 3 known combos, 3 of them two-card. 2 official rulings.

Bracket

B1 Exhibition — Not in the same deck as its two-card combo partners: Knowledge Pool, Possibility Storm, Erayo, Soratami Ascendant // Erayo's Essence
B2 Core — Not in the same deck as its two-card combo partners: Knowledge Pool, Possibility Storm, Erayo, Soratami Ascendant // Erayo's Essence
B3 Upgraded — Not in the same deck as its early two-card combo partners: Knowledge Pool, Possibility Storm
B4 Optimized — allowed: No restriction beyond the banned list
B5 cEDH — allowed: No restriction beyond the banned list

Two-card combo with Knowledge Pool, Possibility Storm, Erayo, Soratami Ascendant // Erayo's Essence (early with Knowledge Pool, Possibility Storm)

Bracket: Lotus Vault analysis, with Commander Spellbook flags

3 known combos, 3 of them two-card.

Knowledge Pool + Rule of Law
Produces: Exile all spells players cast from their hand, Players can only cast one spell per turn, Lock
View on Commander Spellbook
Possibility Storm + Rule of Law
Produces: Players can't cast spells from their hand, Lock
View on Commander Spellbook
Erayo, Soratami Ascendant // Erayo's Essence + Rule of Law
Produces: Opponents can't resolve any spell for the rest of the game, Lock
View on Commander Spellbook

2019-07-12 · Wizards of the Coast
Rule of Law looks at the entire turn to see if a player has cast a spell, even if Rule of Law wasn’t on the battlefield when that spell was cast. Notably, you can’t cast Rule of Law and then cast another spell during the same turn.
2019-07-12 · Wizards of the Coast
If you cast a spell that was countered, you can’t cast another spell during the same turn.

Rulings: Scryfall · Wizards of the Coast