Keep Out

Four damage is a genuine removal number, enough to answer most of what fair white decks want dead, but the tapped-creature clause taxes it hard: the first mode only functions once a creature has committed to attacking or an ability that taps it. White does not get to point premium burn wherever it likes, so this asks the caster to wait for the tap, then punish the tempo swing at instant speed. That timing window is the balancing act. A creature idle on defense is untouchable until it does something, and the payoff for patience is a clean four-point answer to a threat that overextended. The second mode reaches back to white's oldest license, the color's long-standing warrant to break auras, sagas, and static locks. Bolting that onto conditional removal converts a narrow answer into a card you can nearly always spend: when the tapped-creature line has no target, the enchantment out is still live, and when the board sits quiet, the burn half waits for someone to swing. Modal instants succeed or fail on how seldom both halves are dead at once, and the pairing here is picked so at least one of the two decisions in front of you almost always resolves into something worth casting.