President Trump and the Republican National Committee are strongly considering Dallas as the site of an unusual midterm convention later this year, according to two people with knowledge of the discussions. Republicans are working to finalize the plan as they seek to rally their voters in the face of political headwinds. Some details must still be finalized, including the exact dates, and officials said formal paperwork still needed to be signed. But Trump advisers who are looking to parade their candidates and rally the base are close to settling on Dallas over other options, which had included Las Vegas, according...