.Biden preparing to block Nippon Steel acquisition of united state Steel The Washington PostU.S. Steel states it might leave behind Pittsburgh if Nippon package fails as Biden organizes to block requisition Pittsburgh Post-GazetteBiden Expected to Block U.S. Steel Takeover The New York TimesExclusive|U.S. Steel Warns of Vegetation Closings if Purchase Collapses The Commercial JournalBiden prepared to block US Steel investment through Nippon Steel CNN.