.Biden prepping to block Nippon Steel investment of U.S. Steel The Washington PostU.S. Steel says it could leave Pittsburgh if Nippon offer fails as Biden intends to block out requisition Pittsburgh Post-GazetteBiden Expected to Block U.S. Steel Requisition The New York TimesExclusive|United State Steel Warns of Plant Closings if Sale Falls Down The Exchange JournalBiden readied to block out US Steel investment through Nippon Steel CNN.