"For Iran, this is the recognition of its legitimate right to create a nuclear program - including enrichment - and a backing off by the P5+1 from its zero-enrichment position."

"For the P5+1, it is an absolute prohibition on Iran from creating a nuclear bomb, and having Iran clear up ambiguities in its nuclear program to the satisfaction of the International Atomic Energy Agency," Mousavian writes.

The West also needs to abandon calls for regime change and accept that "crippling sanctions, covert actions, and military strikes might slow down Iran's nuclear program but will not stop it."

"In fact, it is too late to demand that Iran suspend enrichment activities," Mousavian writes. "It mastered enrichment technology and reached break-out capability in 2002 and continues to steadily improve its uranium-enrichment capabilities."

The so-called "break-out" capability refers to the ability of a country to construct a nuclear weapon.

A U.S. think tank, the Institute for Science and International Security (ISIS), has said that capping Iranian uranium enrichment at 5 percent purity level compared with the 90 percent needed for a bomb could form part of an interim deal that would give time for more substantial negotiations.

This and other priority measures would "limit Iran's capability to break out quickly," ISIS said in a report.

Among the things the West should offer to Iran is a package that includes recognition of its nuclear rights, ending sanctions, and "normalization of Iran's nuclear file." In return, Iran should offer the IAEA full transparency and permit the most intrusive inspections possible.

(Editing by Philip Barbara)