Since the violence in Tehran started and Obama adopted a "no interference" policy, he has been under pressure to get America involved with what's happening in Iran.

Obama said that the world was "appalled and outraged" at what has been happening, but fell short of actually threatening any consequences. 

He praised the "courage and dignity" of the protesters, especially the women that are also marching. 

Obama believes that Iran has taken his comments and twisted them to insinuate that he is encouraging the Iranian citizens to protest and riot. There are also reports suggesting that the CIA is behind all of this.

After the further riots over the weekend, and following the death of Neda Agha Soltan in the middle of the street, the White House have agreed that Obama needs to take a tougher stand.  

As Obama has failed in convincing the Iranian leaders and government to curb their violence on their citizens, it also seems likely that any prospects for dialogue with Iran over its nuclear program are finished also.