As revolutionary states whose ruling ideologies are deeply hostile to both Israel and the United States, Iran and Venezuela are natural allies: There’s a reason Hezbollah has been so at-home in the ever-backsliding South American country. A new Bloomberg report is a reminder that Venezuela also provides a tangible service to Iran, by giving the Islamic Republic illicit access to foreign currencies that the sanctions regime still block Iran from holding. The Bloomberg story describes an alleged laundering arrangement in which the Venezuelan state oil company dramatically overpaid an Iranian construction firm for a project largely organized as a means of delivering foreign currency to the Iranian government.

The ingenuity of the construction scheme attests to the Iran-Venezuela money laundering relationship’s remarkable versatility. According to the Bloomberg report, in 2008, the Iranian Bank Saderat, at the time on the U.S. Treasury Department’s Specially Designated Nationals list, helped launch a Venezuelan financial institution called Banco Nacionale de Desarrallo, which Saderat also owned. The purpose of Iranian ownership of the bank was to set up a “nesting scheme” whereby Iran could use a Venezuelan bank to surreptitiously access the U.S. financial system using various non-sanctioned third-parties. A new round of western sanctions on Iranian-linked Venezuelan financial institutions limited the nesting arrangement’s effectiveness, but several legal and political experts, including former Manhattan district attorney Robert Morgenthau, discovered evidence of continuing ties between the Iranian regime and the Venezuelan financial system. In 2013, an Iranian director of Banco Nacionale de Desarrallo was detained in Germany for failing to declare a check worth 300 million Venezeulan bolivars, or $70 million, at customs.

In contrast to these complex illicit financial relationships, the laundering mechanism described in the Bloomberg article is fairly straightforward. Venezuela’s state oil company overpaid three Iranian construction companies on projects that went largely unbuilt. This is far from an ideal laundering arrangement because the overpayment required the veneer of a justifiable construction project, as well as the logical headache of actually executing on some of it. (Bloomberg notes that “only a couple thousand” of the 24,000 contracted units ever materialized, which is still an awful lot of apartments to have to build.) Even so, the contracts were worth some $2.3 billion, money which could go a long way in a country with an official annual military budget of $19 billion, assuming all of it ended up in Iran.

The Bloomberg story connects to one of the more problematic issues in U.S.-Iranian diplomacy, one that had the potential to unsettle last year’s landmark nuclear agreement even before Donald Trump’s election. Iran only needs a convoluted money laundering infrastructure in a failing semi-pariah state like Venezuela because the Joint Comprehensive Plan of Action (JCPOA) hasn’t yet resulted in the regime being permitted to legally access the U.S. dollar.

Although the JCPOA eventually removes most U.S. and international sanctions on Iran, Washington and Tehran haven’t quite agreed on whether the deal entitles Iranian financial institutions to carry out dollar transactions or purchase the world’s strongest reserve currency this early in the deal’s lifecycle. Back in April, there was some evidence that the U.S. Treasury was considering issuing waivers that would allow specific U.S.-based financial institutions to clear dollar transactions for certain Iranian counterparts. The waivers never materialized, and dollar access—an issue the two sides couldn’t work out even with the pro-engagement Barack Obama in office—now promises to be even more of a sticking point in deal implementation once Trump and his team of Iran deal skeptics enter the White House. Trump’s election all but ensures that Iran will have to continue using cumbersome laundering schemes to access convertible foreign currencies, yet another reason the JCPOA will be under potentially critical strain for the first few years of the new administration.