Trump claim on N. Korean nukes may underestimate program

U.S. President-elect Donald Trump took to Twitter to vow that North Korea won't develop a nuclear weapon capable of reaching parts of the United States. But it might already have done so.Views vary, sometimes wildly, on the exact state of North Korea's closely guarded nuclear and missile programs, but after five atomic test explosions and a rising number of ballistic missile test launches, some experts believe North Korea can arm short- and mid-range missiles with atomic warheads.That would allo