Arms-control agreements tie the earth-shattering drama of great power politics to a set of vague and highly technical obligations and tradeoffs, the larger significance of which can sometimes only be glimpsed in retrospect. Moreover, they’re meant to last in perpetuity: Just as the Non-Proliferation Treaty is intended to permanently halt the spread of nuclear weapons, Secretary of State John Kerry has said there’s “no sunset” on parts of the nuclear deal, in which Iran has agreed to never develop nuclear weapons. When an agreement is meant to last forever, it’s impossible to say at a given moment whether it’s been a decisive success or failure. It seems fair to predict that the debate over the Iran deal will never end, just as the debates over the Non-Proliferation Treaty, the Comprehensive Test-Ban Treaty, and the Anti-Ballistic Missile Treaty haven’t ended.This summer has offered scattered clues as to whether the most important foreign-policy development of Barack Obama’s presidency is working out. So far, most observers agree that Iran appears to be sticking to the letter of its obligations under the Joint Comprehensive Plan of Action (JCPOA). At the same time, the past few months have produced plenty of fodder for deal critics, including revelations of a secret deal provision on uranium-enrichment centrifuge development, and news of a $400 million “ransom” payment to the Iranian regime made in unmarked bills in currencies that were not numbered sequentially, and which appear to have wound up in the hands of Iran’s terror-sponsoring Revolutionary Guard. Reporting this week suggests that the actual amount of the cash payments was $1.7 billion.The Iran deal and its diplomatic consequences will likely be debated for decades to come, and critics and supporters of the agreement will find plenty of validation from the events of this past summer. Here are some of the biggest developments:The $400 million/$1.7 billion “ransom.” On Jan. 17, Secretary of State John Kerry announced that the United States had settled a 34-year-old dispute with Iran over $400 million that Tehran had claimed at the Hague-based U.S.-Iran Claims Tribunal since 1981. In 1979, the Shah of Iran transferred $400 million to the United States as part of an arms deal but was overthrown before the weapons could be delivered. Naturally, the United States was hesitant to return hundreds of millions of dollars to the government that had supplanted the shah, sacked a U.S. embassy, repeatedly attacked American targets, and snagged a spot on the country’s state-sponsors-of-terror list. Five successive U.S. presidents opted not to pay Tehran.That all changed Jan. 17, which also happened to be the day after four U.S. citizens were released from Iranian government custody. At that point, paying back the decades-old debt—inasmuch as the United States can be indebted to a country with which it has no diplomatic relations—suddenly became a no-brainer. As Kerry said, “Iran’s recovery was fixed at a reasonable rate of interest, and therefore Iran is unable to pursue a bigger tribunal award against us, preventing U.S. taxpayers from being obligated to a larger amount of money.”The story blew up over the summer when Jay Solomon of The Wall Street Journal revealed just how and when the first $400 million of that payment occurred. On Aug. 3, Solomon reported that the United States had delivered $400 million in euros and Swiss francs to Tehran by plane around the same time as the prisoner release. Two weeks later, State Department spokesman John Kirby conceded that the release of the Iranian-held hostages was contingent on the money’s arrival. To deal critics, it at least appeared that the administration had used the decades-old debt as a mechanism for paying a very large cash hostage ransom to a deeply anti-American regime.The administration said the United States negotiated a good deal with Iran over paying the $400 million and the accumulated interest—and it’s true that Washington might have eventually had to pay the money back to some future Iranian government in order for full diplomatic relations to be restored. But even the most generous interpretation of events raised questions: Why did the matter of the $1.7 billion payment have to resolved with this Iranian government, and at this exact moment? In an Aug. 4 press conference, Obama claimed the United States had to pay the Iranians in cash because the United States did not have a banking relationship with Tehran. But during the era of peak international sanctions, the United States and its partners developed systems to ensure permissible transactions with Iran, such as certain oil purchases, didn’t expand Tehran’s foreign-currency reserves: For instance, India would purchase Iranian oil through an escrow account that ensured Iran would be paid in Iranian riyals rather than the more convertible Indian rupee. Iran has gotten billions in sanctions relief since 2013 without having to receive cash payments in convertible foreign currencies. And for good reason: Swiss francs and euros have an awful lot more purchasing power than Iranian riyals in Lebanon, Syria, Iraq, or any number of places where Iran maintains foreign proxy forces.In June, Iran announced it was boosting its military spending $1.7 billion, an amount exactly equal to the January payment.The Boeing deal. The U.S. aerospace company was a high-profile supporter of the Iran deal, which included a provision legalizing foreign aircraft sales to the country. Boeing got its long-awaited opening to the Iranian market in June, when it agreed to sell 109 aircraft to state-owned Iran Air in a deal worth some $25 billion. The development produced immediate congressional backlash, with the House of Representatives passing an amendment aimed at blocking the deal in July. Critics raised concerns that the aircraft would be used to ferry Iranian weapons and personnel to the battlefield in Syria. As of late August, Boeing still had not received the U.S. government licenses needed to complete its sale with Tehran.Pickering’s conflict of interest. Thomas Pickering is one of the giants of U.S. foreign policy, a former ambassador to Russia, Israel, Jordan, and the United Nations who has served both Republican and Democratic presidents. He became one of the public faces of the pro-Iran deal campaign, and his voice counted as much as anybody’s: He argued in favor of the deal at a contentious Intelligence Squared debate, and published op-eds arguing in favor of the deal, including one in Tablet magazine.As it turned out, Pickering was far from the disinterested “wise man” he appeared to be. On June 22, the Daily Beast reported that Pickering was a paid consultant for Boeing, which was eager to sell aircraft to Iran. Boeing stood to profit handsomely from the Iran deal, which included a provision stating that “the United States will … allow for the sale of commercial passenger aircraft and related parts and services to Iran.” At the moment, Boeing is attempting to complete a $25 billion sale with the Iranian government.Pickering and the deal’s supporters didn’t seem to think this undisclosed conflict of interest was really that big of a deal, or even any kind of a deal: On July 12, just a few weeks after The Daily Beast’s story, Pickering’s name appeared as one of the signatories on a letter to President Obama supporting the agreement on its one-year anniversary and urging him to strengthen ties with Tehran.The secret provision(s). It turns out that at least one important element of the JCPOA didn’t make it into the publicly available text of the deal. On July 18, the Associated Press reported that under the deal, Iran would be permitted to bring advanced centrifuges online in year 11 of the agreement. The AP likely based its information on a document describing Iran’s future nuclear research and development, which was submitted to Congress in July of 2015, along with 17 other documents related to the Iran deal.So while this crucial research-and-development provision of the deal wasn’t technically kept secret, and doesn’t actually conflict with the text of the JCPOA, the AP report was the first time the broader American public learned about it.Heavy water purchases. Although the Iran deal obligates signatories to assist in the development of the country’s nuclear program, it says absolutely nothing about the United States having to purchase heavy water from the country. Nevertheless, on April 22, the United States announced it would buy $8.6 million in heavy water from Tehran, a move that effectively turns the United States into a beneficiary of a once-illicit nuclear program. At the same time, the arrangement removed 32 metric tons of sensitive nuclear material from the country as well, neutralizing a potential proliferation concern.The purchase was a target of bipartisan criticism, with the House on May 1 voting to bar the United States from future heavy-water purchases.Ballistic-missile tests. The JCPOA’s implementation required the U.N. Security Council to remove a number of resolutions pertaining to the country’s nuclear program, including those prohibiting ballistic-missile testing. That means the ballistic-missile tests Iran conducted in May and July were not violations of international law. Neither did they represent a breach of the Iran deal, as the Joint Commission established under the deal that to monitor implementation did not declare them to be a violation.Even so, Iran tested potential nuclear-delivery vehicles on multiple occasions over the summer, something that resulted in additional U.S. sanctions this past May.Secret exemptions. On Sept. 1, the Institute for Science and International Security reported the Joint Commission had secretly allowed Iran to exceed the JCPOA-mandated cap on its low enriched-uranium stockpile in order to hasten the agreement’s implementation. The report alleged that a crucial aspect of the deal was hollowed out for Iran’s benefit and without a public disclosure.The report produced a spirited debate among nonproliferation experts, with deal supporters arguing that all arms-control treaties have had a degree of flexibility, and that in this case, the Joint Commission had functioned in a way consistent with its role under the JCPOA. ISIS (it existed long before the terror group), which is led by former U.N. weapons inspector and nuclear physicist David Albright, maintains that the Joint Commission had substantially altered Iran’s obligations under the deal, and in a nontransparent fashion.Iran’s new missiles. For critics, one of the more objectionable aspects of the nuclear deal was that it permitted Iran to run non-fissile materials centrifuges at Fordow, a hardened facility inside of a mountain on a Revolutionary Guards base whose existence Iran had long concealed from the international community. Another one of the most controversial aspects of the Iran deal was Tehran’s success in getting the P5+1 to agree to remove all conventional weapons and ballistic missile-related restrictions on the country within eight years of implementation day.These two potential shortcomings of the agreement converged in August, when Iran deployed newly acquired Russian S-300 missiles at Fordow. The rationale is clear enough: Nearly all limitations on Iran’s uranium-enrichment and centrifuge research will be removed within 15 years of the agreement, meaning Iran will eventually be allowed to run fissile material through centrifuges at Fordow. The S-300 is one of the world’s most sophisticated anti-aircraft systems and can strike targets at an altitude of 19 miles, and at a range of over 90 miles. The S-300 deployment makes an aerial attack on one of the Iran’s most protected nuclear facilities an even more daunting challenge.Confrontations at sea. The U.S. and Iranian naval forces haven’t been all that great at sharing the Persian Gulf lately—back in January, Iran captured and briefly detained 10 U.S. Navy personnel who had allegedly drifted into Iranian territorial waters. But Iran’s open harassment of U.S. vessels became a troubling pattern toward the end of the summer, with Iranian boats passing within 100 yards of a U.S. coastal patrol ship in early September. According to CNN, the U.S. Navy has had 31 “unsafe encounters with Iranian vessels in the Persian Gulf” this year, up from 25 for the whole of 2015.***You can help support Tablet’s unique brand of Jewish journalism. Click here to donate today.