Dentons is supercharging its ambitions for the United States, announcing combinations with two major regional players as a starting point for its campaign to build what it calls the first “national” U.S. law firm.

Already the largest firm in the world, Dentons is adding over 300 attorneys by combining its existing U.S. operations with the Midwest’s Bingham Greenebaum Doll and Pittsburgh-based Cohen & Grigsby. The moves are the first salvos in a campaign the firm has dubbed ”Operation Golden Spike”—named for the ceremonial 17.6-karat gold spike that tied together the Transcontinental Railroad in 1869.