Iran has filed a lawsuit at the International Court of Justice (ICJ) seeking a court order to lift US sanctions against them. The sanctions were imposed in recent weeks as part of the US withdrawing from the P5+1 nuclear deal, and subsequently trying to reimpose nuclear sanctions on the Iranians.
Iran argues that the unilateral sanctions are in violation of he 1955 Treaty of Amity and Economic Relations signed between Iran and the US in 1955. The treaty has been cited in previous Iranian lawsuits against the US at the ICJ.
This is the first time, however, that Iran has pushed a lawsuit regarding the treaty to prevent US sanctions. This may reflect that in the past, US sanctions tended to be part of international measures, while in this case, the US unilaterally withdrew from the existing diplomatic deal, and seeks to reimpose sanctions unilaterally, pushing the rest of the world to comply with them.
The US hasn’t commented on the new lawsuit, though since previous administrations have cited the 1955 treaty with Iran in other contexts, so it will be difficult for the current administration to claim that it isn’t still effectively in place.