.Biden preparing to obstruct Nippon Steel purchase of U.S. Steel The Washington PostU.S. Steel claims it could possibly leave behind Pittsburgh if Nippon deal falls through as Biden considers to shut out requisition Pittsburgh Post-GazetteBiden Expected to Block U.S. Steel Requisition The The Big Apple TimesExclusive|U.S. Steel Warns of Vegetation Closings if Purchase Breaks Down The Commercial JournalBiden prepared to obstruct United States Steel investment by Nippon Steel CNN.