Major firms which oppose a proposed deal to merge Medco Health Solutions Inc and Express Scripts Inc feared retaliation and declined to publicly discuss the deal, said Senator Herb Kohl, head of the Senate Judiciary Committee's antitrust panel. Senator Richard Blumenthal also took aim at the estimated $26 billion deal, saying it was "problematic" and asking the companies if they would be willing to accept major divestments to win approval for the deal. The proposed transaction, which was announced in July, would combine two of the three U.S. pharmacy benefit managers that are large enough to manage prescription drug benefits for nationwide companies.