A second round of nuclear talks between the United States and Iran is underway, as what both sides are looking for in a deal begins to take shape. Delegations from both countries met in Oman last weekend for talks mediated by the Gulf Arab nation.

That the talks are even happening represents a historic moment, given the decades of enmity between the two countries since the 1979 Islamic Revolution and the U.S. Embassy hostage crisis.

At risk is a possible American or Israeli military strike on Iran’s nuclear sites, or the Iranians following through on their threats to pursue an atomic weapon.