These remarks are the latest in a series of provocations that include the test-firing of three ballistic missiles last month, in defiance of a UN Security Council resolution that calls upon the Islamic Republic to avoid further work on missiles that are capable of carrying a nuclear warhead. Two previous tests of this kind took place in October and November, and the IRGC has on multiple occasions broadcast images on state television from inside Iran’s missile silos, accompanied by claims that the country’s stockpiles of such weapons have grown so large that the IRGC is running out of storage space.

The persistence of these provocations has been cited by US congressmen and media commentators who are critical of the Obama administration’s nuclear agreement and its more general policies toward Iran. In particular, those critics have recently taken issue with changing Treasury Department rules that some believe are indicative of an effort by the White House to expand upon existing sanctions relief measures associated with the nuclear deal.

Republican congressmen have emphasized that Obama administration officials gave numerous assurances during and after nuclear negotiations that Iran would not gain access to the US financial system and would continue to be subject to sanctions on its missile program, human rights violations, and support for international terrorism. In a Senate Foreign Relations Committee hearing on Tuesday, some of those congressmen reiterated that the emerging rules change appears to undermine those assurances by allowing Iran the indirect use of American financial institutions, via offshore intermediaries.

In that same hearing, Undersecretary of State Thomas Shannon attempted to assuage congressional concerns, to limited effect. On Wednesday, the Associated Press reported that two Republican senators, Marco Rubio of Florida and Mark Kirk of Illinois, declared their intention to introduce legislation that would expressly forbid the type of activity that the Treasury Department is considering, known colloquially as “U-turn transactions.”

In the opinion of these senators and their supporters, this type of prohibition would help to retain some of the economic leverage that the US still retains over Iran in the wake of the nuclear agreement and associated sanctions relief. It would also counteract a trend that Republicans and some Democrats perceive as the ongoing provision of concessions and the avoidance of enforcement measures by the Obama administration.

This perception is arguably undermined by some other measures that the administration has taken in recent weeks, including the imposition of new sanctions on the Iranian ballistic missile program in the wake of last month’s tests. 

Much of the US Congress have been similarly critical of Obama’s Iran policy and have urged much more assertive responses to Iranian provocations and perceived violations of either the letter or the spirit of the nuclear deal.

Such responses may prevent Iran from obtaining the financial resources that it needs to continue pursuing military and ballistic missile development, as many Iranian officials including the supposedly moderate President Hassan Rouhani have repeatedly vowed to do. This is not to say that the Obama administration is explicitly permitting those activities to continue; but it does appear to be confronting them at a different point in the supply chain than the administration’s critics would prefer.

In Tuesday’s Foreign Relations Committee hearing, Undersecretary of State Shannon guaranteed that the US would use its veto power in the UN Security Council to block authorization of any sales of fighter jets and similarly advanced weaponry from Russia to Iran. Such sales became a topic of discussion between the two countries soon after the implementation of sanctions relief in accordance with the nuclear agreement.