.Biden prepping to block Nippon Steel investment of U.S. Steel The Washington PostU.S. Steel states it might leave Pittsburgh if Nippon offer fails as Biden prepares to shut out requisition Pittsburgh Post-GazetteBiden Expected to Block U.S. Steel Requisition The New York City TimesExclusive|United State Steel Warns of Vegetation Closings if Purchase Collapses The Exchange JournalBiden prepared to block out US Steel investment by Nippon Steel CNN.