For those in Tehran and Washington who have spent a generation trying to redefine the US-Iranian relationship, Jan. 16, 2016, was a day of victories that had long been elusive. In the morning, Iran was found to have complied fully with the terms of the historic Joint Comprehensive Plan of Action, marking the deal’s Implementation Day, and as such, triggering the lifting of all nuclear-related sanctions. Almost immediately, four Iranian-Americans jailed in Tehran’s Evin Prison were freed and hustled to Mehrabad Airport to catch a private plane bound for Germany. At the same time, an unmarked plane carrying $400 million in non-dollar currencies landed in Tehran, marking the successful settlement of a disputed US-Iranian arms sale dating back to 1979. Proponents of diplomacy saw the dramatic events as vindication of the notion that festering disputes between the two countries could be resolved through talks. Conservative skeptics of the nuclear deal in the United States and Iran, however, saw something very different — a hefty ransom paid to free the jailed American citizens.

Despite the fraught US-Iranian political relationship, legal settlements between the two countries historically have not been accompanied by the level of controversy surrounding this latest case. This has largely been due to the effective work of the Iran-United States Claims Tribunal, set up at The Hague by the terms of the Algiers Accord that resolved the 1979-81 US Embassy hostage crisis. The tribunal consists of an equal number of Iranian, American and neutral arbitrators who have worked on some 4,700 claims since 1981. To date, the tribunal has ordered Iran to pay more than $2.5 billion to Americans for broken business relationships and facilitated the settlement of restitution payments to the victims of the US missile attack on an Iran Air plane in 1988. Its work has progressed quietly, largely without fanfare or controversy, and has resulted in the peaceful resolution of many disputes between the two former allies.

Private American claims against Iran have all now largely been resolved, and most of the remaining cases before the claims tribunal are Iranian claims against the US government. With about 14 controversial cases outstanding, each with an estimated time frame of five years to resolve, the United States faces the prospect of paying significant settlements to Iran for the next 70 years. Some of the remaining cases include explosive Iranian claims, such as accusations of covert CIA activities breaching the Algiers Accord, meaning the claims are likely to be even more politicized than the recent settlement of a relatively straightforward canceled arms deal.

Indeed, the “ransom” controversy may be just the beginning of a long period of outrage in the United States over “pallets of cash” regularly arriving in Tehran to settle the remaining cases at the claims tribunal. The arms sale settlement makes certain things clear: First, the resolution of valid legal claims between the United States and Iran will take an exceptionally long time to resolve through the tribunal system; second, each future settlement will be accompanied by dramatic cries of capitulation from one side and triumphalist declarations from the other; and third, each resulting controversy will be used to undermine any attempts at a political understanding between the two governments.