Days after President Joe Biden joined his election rival Donald Trump in voicing concern about a Japanese purchase of U.S. Steel, the manufacturer began touting the benefits of the deal on billboards near its factories from Alabama to Pennsylvania. The billboards may be the most public signs of what some Japanese officials say in private - that despite high hurdles, Nippon Steel could still steer through the fraught $15 billion acquisition of the iconic American manufacturer. The deal may well hinge on whether regulators avoid election-year politics by clearing the acquisition after Nov. 5, and, critically, on whether Nippon Steel can win over the influential United Steelworkers (USW) labour union.