WU's gameplan revolves around Force of Will, Daze, Stifle, and Consign to Memory protecting Tamiyo and Phelia while Swords to Plowshares answers our few creatures. Nothing in their deck targets us as a player, so Leyline of Sanctity (which only gives us hexproof, not our creatures) does nothing here and stays in the sideboard. Instead we bring in Thoughtseize to strip a Force of Will or Swords to Plowshares before we go for the combo. To make room we cut Destroy the Evidence, which is too slow and expensive here, along with Memory's Journey and Bridge from Below, which do little against a tempo plan that exiles our creatures. Their real threats are the free countermagic (Force of Will, Daze) plus Stifle and Consign to Memory on our triggered abilities, so sequence around Wasteland and hold Pact of Negation for their last counter.