.Biden prepping to block Nippon Steel purchase of united state Steel The Washington PostU.S. Steel states it might leave Pittsburgh if Nippon bargain falls through as Biden organizes to block takeover Pittsburgh Post-GazetteBiden Expected to Block U.S. Steel Takeover The The Big Apple TimesExclusive|U.S. Steel Warns of Vegetation Closings if Sale Breaks Down The Exchange JournalBiden prepped to block United States Steel purchase by Nippon Steel CNN.