.Biden preparing to block Nippon Steel purchase of U.S. Steel The Washington PostU.S. Steel states it could leave Pittsburgh if Nippon package flops as Biden intends to obstruct requisition Pittsburgh Post-GazetteBiden Expected to Block USA Steel Requisition The New York City TimesExclusive|USA Steel Warns of Vegetation Closings if Sale Collapses The Exchange JournalBiden readied to block United States Steel acquisition by Nippon Steel CNN.