Iranian President Mahmoud Ahmadinejad

Iranian President Mahmoud Ahmadinejad

Atta Kenare/AFP/Getty Images

Iranian President Mahmoud Ahmadinejad holds a press conference in Tehran on Oct. 2, 2012 where he said Iran will not back down on its nuclear program despite economic problems caused by Western sanctions. The most persistent challenge may remain Iran, where economic sanctions so far have failed to halt the suspected pursuit of nuclear weapons.