As Mr. Trump prepares to make his first post-presidency trip to the border next week, the Government Accountability Office has delivered a scorching report card on his border wall, calculating that he only completed 69 miles of the wall system he promised the country — not the more than 450 miles he claimed. The GAO said that the Trump administration front-loaded construction of fence panels in order to meet Mr. Trump’s deadline, and that meant shortchanging the roads, lights and other technology that made up the highly touted “wall system.” While 458 miles of new fence panels were erected before Mr. Trump left office, just 69 miles had all the bells and whistles the Border Patrol planned.