.Biden prepping to obstruct Nippon Steel purchase of U.S. Steel The Washington PostU.S. Steel mentions it could leave Pittsburgh if Nippon bargain falls through as Biden plans to shut out requisition Pittsburgh Post-GazetteBiden Expected to Block U.S. Steel Takeover The New York TimesExclusive|United State Steel Portend Plant Closings if Purchase Falls Down The Commercial JournalBiden prepared to shut out United States Steel investment through Nippon Steel CNN.