Iran nuclear talks show progress amid doubt

In an interview with CBS News this weekend, President Obama said the U.S. will walk away from nuclear negotiations with Iran unless it can verify that country is not developing nuclear weapons.

The talks have dragged on for two years, and this week, there were signs of progress.

It's no wonder the diplomats working on the nuclear agreement looked pleased this week, there's been a recent breakthrough.

"We're closer than we've ever been," said Mark Fitzpatrick, an arms control analyst at Strategic Studies Institute in London.

Iran -- its economy reeling from low oil prices and U.S.-led sanctions -- has finally made a key concession.

"The Iranians agreed to limits they'd never agreed to before," Fitzpatrick said. "They had been talking about not cutting anything, but now they're ready to cut back significantly."

In a nutshell - they're ready to cut the number of centrifuges used to make enriched uranium - a component of weapons - from 19,000 to between 6,000 and 7,000.

And crucially - they'll reduce the amount of enriched uranium they keep on hand from 7.5 tons to around 700 pounds.

Secretary of State John Kerry was in Saudi Arabia this week to reassure Iran's nervous neighbors that this is a good deal for them too.

"Obviously, the outcome of these negotiations will be of major consequence to the United States yes, but really to the entire world," Kerry said.

He has to convince everyone -- especially skeptics in the U.S. -- that the new limits would give the world a year's warning if Iran ever did decide to make a bomb.

"I think frankly one year is more than enough," Fitzpatrick said. "You need time to detect any breakout, to confirm that the violation is real, have a diplomatic solution attempts, and if that fails - to take military action. All of that can be done in 6 months I think."

A deal may be as close as it's ever been, but the Iranians want all sanctions against them lifted in return for their concessions and that's just not going to happen, so there's a lot of hard bargaining to go.