As nuclear negotiations resume June 16 in Vienna, a new paper by a veteran US Iran expert and congressional analyst lays out options for unwinding US sanctions that include initial waivers by President Barack Obama and the 2016 expiration of a key piece of legislation that has impeded foreign investment in Iran’s energy sector.

According to the paper, written by Kenneth Katzman and slated to be presented at an Atlantic Council event along with a companion report on lifting European sanctions, the Obama administration “might decide to allow the Iran Sanctions Act to sunset” when it expires on Dec. 31, 2016, shortly before Obama leaves office. Expiration of the act “would reopen Iran’s energy sector to unimpeded foreign investment and would enable Iran to begin expanding oil and gas production again after many years of stagnation,” notes Katzman, writing in his personal capacity and not on behalf of his employer, the Congressional Research Service. He adds that Congress could vote to extend the act, as it has repeatedly done since the law was first passed in 1996, but the president could exercise his veto authority.

The issue of sanctions relief is a key element in what both US and Iranian negotiators have called a Rubik’s Cube in an attempt to describe the complexity of fitting together verifiable curbs on the Iranian nuclear program with a phased removal of penalties that have crippled the Iranian economy. Katzman's paper could provide a road map both feasible for the White House and acceptable to Iran, whose negotiators have indicated that they do not expect quick action by Congress to repeal sanctions legislation.

Since the 1979 hostage crisis, but especially in the last few years, Iran has been the target of a plethora of US and European penalties. US sanctions include 10 statutes and 26 executive orders alone. Iran has also been penalized in four resolutions by the UN Security Council.