Is Infinite Authority legal in Standard, Modern, and Commander?

Infinite Authority is legal in: Legacy, Vintage, Commander.

Infinite Authority

Q: What type of card is Infinite Authority?

Infinite Authority is an Enchantment — Aura. Its oracle text reads: "Enchant creatureWhenever enchanted creature blocks or becomes blocked by a creature with toughness 3 or less, destroy the other creature at end of combat. At the beginning of the next end step, if that creature was destroyed this way, put a +1/+1 counter on the first creature."

Enchantment — Aura

Enchant creature<br>Whenever enchanted creature blocks or becomes blocked by a creature with toughness 3 or less, destroy the other creature at end of combat. At the beginning of the next end step, if that creature was destroyed this way, put a +1/+1 counter on the first creature.

Set Legends

Rarity Rare

Artist Douglas Shuler