The 2012 election was supposed to be a test of a weakened president and his ambitious and unpopular health care plan. Challengers saw a chance to take down a Democratic incumbent after the excitement of his history-making election had faded.

Designing and building nuclear bombs is one of the U.S. government’s most secretive activities. But the PBS NewsHour recently was granted unprecedented access to a number of highly classified facilities, where the world’s most destructive weapons are now being updated…