After months of negotiations, world powers announced an accord with Iran Tuesday over Tehran's nuclear program that, according to the deal's most ardent supporters and detractors, may either pave the way for a historic rapprochement between the Islamic Republic and the West or enable the Iranian leadership to pursue its destabilizing agendas in the Middle East unchecked.

The more likely prospect, as most of the deal's proponents seem to realize, is something in between. The deal, they argue, is the most practical solution to a vexing geopolitical challenge. It places the nuclear program of a regime few trust under strict, verifiable controls, and averts the likelihood of yet another military escalation in an already fractious region.

The focus now shifts to the implementation of the agreement, which faces political obstacles in Washington and, to a lesser extent, Tehran.

Questions remain about how ironclad the provisions of the agreement will be in ensuring Iran does not "cheat," or breach any of the terms of the deal. There will be a lot of political debate about this in the weeks ahead, but on Tuesday, it seemed a good number of Western nonproliferation advocates and arms control experts were satisfied with the Vienna agreement.

That included Thomas Shea, a veteran former inspector with the IAEA, the U.N.'s atomic agency, who oversaw the design and implementation of safeguards for the world's evolving nuclear facilities.

"This is a stunning accomplishment," said Shea, who is now a Vienna-based consultant, speaking to WorldViews in Washington. "I’ve been a part of this business for 40 years at this point and I’ve never seen anything that begins to approach the comprehensiveness of this agreement."

WorldViews earlier detailed the terms of the deal, which forces Iran to dramatically reduce its number of centrifuges -- devices used to enrich uranium gas into more fissile material -- as well as its stockpile of enriched uranium, and commit to long-term restrictions on the nature of the work that can be carried out in its nuclear facilities.

But what if Iran doesn't abide by the terms of the agreement?

The IAEA, says Shea, has since its inception been "preparing for the role" of monitoring this sort of deal, and will be routinely flying in teams of inspectors to verify Iran's continued adherence to the provisions of a final agreement.

The deal clinched in Vienna ensures that the IAEA has round-the-clock access to Iran's nuclear facilities and is allowed to maintain state-of-the-art sensors, cameras and other surveillance equipment on site. The expectation of some for "anywhere, anytime inspections" on Iran's facilities, Shea says, is something of a misnomer, given that's hardly been common verification practice in the past. It also appears that the Iranians have backed down from an earlier position refusing inspections of the country's sensitive military sites.

The Economist explains:

Inspectors will not be able to conduct “anywhere, any time” visits. Instead, they will have to give grounds for their concerns about prohibited activities and give the Iranians an opportunity to address them before access is made mandatory by the joint commission. All this must take place within two weeks. Refusal by Iran to provide inspectors access that persisted for more than another week would be deemed a violation of the agreement and therefore subject to re-imposition of sanctions.

My colleagues Carol Morello and Karen DeYoung offer more detail:

Once it submits a request to Iran to visit an “undeclared” facility, the IAEA and Iran will have 14 days to agree on the terms of access. If IAEA concerns are not met within that period, a joint commission made up of the seven negotiating countries — Iran and the United States and its partners — plus the European Union, will have up to seven days to review the dispute and decide what Iran needs to do.
Only five of the eight members need to agree, effectively ensuring that Iran, Russia and China cannot prevail if they vote together. Iran then has three days to implement the decision. If it does not, “then we can begin snap-back” of sanctions, a [U.S.] administration official said.

The process may seem cumbersome, and another former IAEA official has expressed concerns over the days it may take to wrangle permission for access. Israeli Prime Minister Benjamin Netanyahu, one of the deal's most outspoken critics, told NPR on Wednesday that this procedure is "like telling a drug dealer: ‘We’re going to check your meth lab in 24 days.'"

But the IAEA, argues Shea, with logistical help from other member states, is well positioned to detect whether Iran is in breach of its commitments or conducting clandestine work on a nuclear weapon.

Here's what's in the Iran nuclear deal, explained in 60 seconds. (Gillian Brockell and Julio C. Negron/The Washington Post)

It has learned from its shortcomings in the 1990s, when regimes in North Korea and Iraq exposed weaknesses in the U.N. agency's safeguards and protocols. It commands a wide spectrum of tools —from highly-sophisticated commercial satellite technology, to infrared and radar imaging to its own laboratories where tests of environmental samples can be carried out — that can be brought to bear.

"There's no comparison between the technologies available now and those 20 years ago," says Shea.

Combined with the likely cooperation of foreign intelligence organizations with the IAEA, the scrutiny on Iran would make it difficult for the regime to hide the construction of another subterranean nuclear facility like the Fordow enrichment plant, which is perched beneath a mountain near the holy city of Qom.

The Iran deal: Who’s for it and who’s not

President Barack Obama, standing with Vice President Joe Biden, delivers remarks in the East Room of the White House in Washington, Tuesday, July 14, 2015, after an Iran nuclear deal is reached. After 18 days of intense and often fractious negotiation, diplomats Tuesday declared that world powers and Iran had struck a landmark deal to curb Iran's nuclear program in exchange for billions of dollars in relief from international sanctions. (AP Photo/Andrew Harnik, Pool)

Moreover, the IAEA will have oversight over Iran's entire nuclear supply chain, from its uranium mills to its procurement of nuclear-related technologies. As Shea notes in a June report posted on the Web site of the Arms Control Association, the U.N. agency will be monitoring Iran's potential "use of black markets or front companies" should Tehran attempt to secretly obtain specialized material for its nuclear program.

"The beauty of this agreement is that Iran gets to keep its buildings and we get to take out all the furniture," writes Joe Cirincione, president of the Ploughshares Fund, which pushes for nonproliferation, and a proponent of the nuclear deal with Iran. He sums up the checks in place:

Iran might want to set up a covert enrichment plant, but where would it get the uranium? Or the centrifuges? Or the scientists? If a 100 scientists suddenly don’t show up for work at Natanz, it will be noticed. If the uranium in the gas doesn’t equal the uranium mined, it will be noticed. If the parts made for centrifuges don’t end up in new centrifuges, it will be noticed. Iran might be able to evade one level of monitoring but the chance that it could evade all the overlapping levels will be remote.

Shea says the IAEA is a scientific institution and will approach the task in "an impassioned way," focused on whether Iran, as a signatory to a raft of agreements (including a new "roadmap" with the IAEA itself), has set out to undermine the accord.

But he is personally "hopeful" that the current deal will mark the beginning of a less acrimonious phase in the IAEA's dealings with the Islamic Republic.

"Iran, through a painstaking negotiated agreement, has established a very formal understanding with six of the most important countries in the planet," said Shea. "To expect Iran would violate this from the outset is somewhat hard to imagine."

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