A coalition of Washington-based business groups on Wednesday sent a joint letter to Treasury Secretary Janet Yellen, asking her to avoid politicizing the ongoing review of Nippon Steel Corp.’s planned acquisition of United States Steel Corp. The letter was sent to Yellen, who heads the Committee on Foreign Investment in the United States that is in charge of the screening, as the major Japanese company is believed to have been making last-ditch efforts to prevent its deal with U.S. Steel from collapsing. “Unfortunately, there have been persistent attempts recently to politicize the committee’s…