High Noon

The tax lands on the whole table and spares no one, its controller included: one spell per turn, flat, no exceptions carved out for the person who cast it. That symmetry is the entire point. White has printed one-sided spell-limiters before, effects that shackled the opponent while the controller kept firing; this one demands you build a deck that wins beneath the same ceiling you're lowering onto everyone else. In practice that means creatures and permanents over reactive spells, since every counterspell and cantrip now eats the only spell you get. It rewards the plan that always wanted to deploy a threat and pass, and it strangles the deck built to chain removal, card draw, and interaction. The sacrifice mode is the escape hatch for the games that grind past the lock's usefulness: give up the enchantment, and red turns it into five damage at any target, ending a game the lock has already dragged down to your clock. That ability also explains the color pairing cleanly enough. Red supplies the reach, white supplies the restriction. The design doesn't sort its victims by archetype; it doesn't care whether you're combo, control, or midrange. It slows every deck to one spell a turn and then asks a single question of the table: who came prepared to win in a world where nobody gets to do two things at once.