Conservative donors have engaged a major GOP consulting firm in Florida to research the feasibility of mounting a late, independent run for president amid growing fears that Donald Trump could win the Republican nomination. A memo prepared for the group zeroes in on ballot access as a looming obstacle for any independent candidate, along with actually identifying a viable, widely known contender and coalescing financial support for that person. The two states with the earliest deadlines for independent candidates, Texas and North Carolina, also have some of the highest hurdles for independents to get on the ballot, according to the...