DALLAS — With less than two months to go until the midterm elections, President Donald Trump and Republicans gather in Texas this week for the first ever GOP midterm convention, as they aim to energize the party's base to turn out in key races that will determine if Republicans keep control of Congress.Democrats and Republicans traditionally hold large nominating conventions during presidential election years. But Trump a year ago floated the idea of a similar gathering ahead of the midterms, to showcase the signature policy achievements he and the Republicans in Congress produced the past two...