A new government audit claims the program to radically increase electronic surveillance along the US border with Mexico is years behind schedule and has run billions of dollars over initial projections. The Government Accountability Office says the network of cameras, radars and fences won’t be completed until 2016, instead of the initial plan for later this year. Auditors also say the border system will cost an additional $6.5 billion in maintenance costs, with no mechanisms to gauge its actual impact.