Anchored by Jake Tapper, The Lead airs at 4 p.m. ET on CNN.
Fmr. national security adviser Stephen Hadley, and the latest on the crisis in Ukraine.
Talks with Iran over its nuclear program stumbled at the 11th hour this weekend, after diplomats taking part had hinted a deal was close.
Days earlier, Iran's foreign minister said a framework was in the works. Two U.S. administration officials told CNN that under the potential deal, Iran would halt enriching uranium to 20%, one step below weapons grade, and refuse to open a heavy water reactor, a second path to a bomb.
So what happened? Secretary of State John Kerry blamed Iran.
"There was unity, but Iran couldn't take it. At that particular moment, they weren't able to accept that particular agreement," Kerry said Monday.
But Iranian Foreign Minister Javad Zarif fired back, blaming the West, particularly France, in a tweet that read, "Mr.Secretary, was it Iran that gutted over half of US draft Thursday night? (A)nd publicly commented against it Friday morning?"
Kerry will brief Capitol Hill Wednesday on the talks. He said "gaps" remain between the West and Iran, though British Foreign Secretary William Hague described those gaps as "very narrow."
Iran experts Aaron David Miller of the Woodrow Wilson International Center for Scholars and Danielle Pletka with the American Enterprise Institute discuss just how narrow those gaps may be, and how a seemingly impending deal fell apart.