.Biden readying to block Nippon Steel purchase of united state Steel The Washington PostU.S. Steel says it could leave behind Pittsburgh if Nippon package falls through as Biden prepares to block out requisition Pittsburgh Post-GazetteBiden Expected to Block United State Steel Takeover The New York TimesExclusive|U.S. Steel Warns of Vegetation Closings if Sale Falls Down The Wall Street JournalBiden readied to obstruct US Steel purchase through Nippon Steel CNN.