Iranian president Hassan Rouhani gestures as he gives a press conference upon his arrival at Tehran's Mehrabad Airport, on September 28, 2013. - 

Iran's new president, Hassan Rouhani, has given the Obama administration an opportunity to start fresh when it comes to diplomatic relations between the two countries. But one big barrier still lasts between the two countries: Economic sanctions.

James Reynolds, BBC's Istanbul correspondent who extensively reports on Iran, says that over the last three decades, the United States has imposed 28 different sanctions on Iran. In exchange for lifting some of those sanctions and for unfreezing billions of dollars in funds, President Obama wants Iran to pump the brakes on some elements of its nuclear program. 

Reynolds says the recent talks in Geneva have been more positive than usual, and that could be a good sign for the Iranian public who have been waiting for a leader who will go out and engage with the rest of the world. But for President Rouhani, it will be a tug of war. 

"Final decisions on matters of state security, foreign policy, and military policy are made by the Supreme Leader himself, Ayatollah Ali Khamenei," Reynolds says. "Mr. Rouhani has to take along the Supreme Leader with him. If he doesn't do that, he wont get a single thing done."