Donald Trump -- who made a fortune in part by lending his name to business ventures on which he left a light touch -- appears poised to take a similar approach to building his ground game. The presumptive GOP nominee has argued he can put as many as 15 states into play this fall, but he lags far behind Democratic front-runner Hillary Clinton in building up troops for a general election battle. Rather than building out teams of his own hires in swing states -- the model previous nominees like Mitt Romney and John McCain relied on -- Trump is...