.Biden readying to obstruct Nippon Steel purchase of USA Steel The Washington PostU.S. Steel says it could possibly leave Pittsburgh if Nippon offer fails as Biden prepares to block requisition Pittsburgh Post-GazetteBiden Expected to Block United State Steel Requisition The New York City TimesExclusive|United State Steel Warns of Plant Closings if Sale Falls Down The Wall Street JournalBiden readied to block United States Steel purchase through Nippon Steel CNN.