One of those boats came within 900 yards of the American ship and did not withdraw until three warning shots were fired into the water. The Mahan had previously attempted to deter the approach using audio sirens, flashing lights, and radio contact, as is standard procedure in such situations.

The report of this incident notes that the last known encounter of this kind occurred on August 25. However, IRGC forces have generally been more transparently belligerent toward the US Navy and other Western vessels. Reports that surfaced more recently than August have described threats to shoot down American Naval jets passing through international airspace near Iran, as well as various propaganda broadcasts declaring the Iranian military and IRGC to be ready for war.

At the time of the previous close encounters, US Navy personnel indicated that the number of such incidents had dramatically increased in comparison with previous years. The provocative moves were widely regarded as efforts by hardliners to compensate for the perception that the 2015 Iran nuclear agreement had dealt a blow to their foreign policy and had increased expectations of cooperative relations between Iran and the West.

Much of the international media has also describes the IRGC’s activities as a response to the more moderate politics of Iranian President Hassan Rouhani. But his moderate credentials have been widely questioned, sometimes with reference to the lack of progress on progress-sounding campaign promises other than the nuclear deal, and sometimes with reference to his refusal to stand up against the IRGC and other hardliners.

In fact, in the latest Iranian calendar year, the Rouhani government’s national budget substantially increased funding for the military and IRGC, even as the administration struggled to turn the nuclear agreement into economic recovery following long periods of severe inflation and unemployment. Those funding priorities have since shown themselves to be an ongoing pattern, as evidenced by the announcement that Tehran was preparing to increase military spending to five percent of the national budget.

The current year’s budget gives approximately two percent to the IRGC alone, according to Reuters, which also reported that the new plan includes the further development of long-range ballistic missiles. Since the conclusion of nuclear negotiations, Iran has conducted several ballistic missile tests, putting it at odds with UN Security Council resolutions calling upon the country to refrain from work on weapons capable of carrying a nuclear payload. US President-elect Donald Trump said in March, “Those ballistic missiles, with a range of 1,250 miles, were designed to intimidate not only Israel … but also intended to frighten Europe and someday maybe hit even the United States.”

In light of these remarks and Trump’s generally confrontational positions regarding Iran, Reuters observes that the new Iranian budgetary plans threaten to put the country on a “collision course” with the incoming US presidential administration. The Daily Caller goes so far as to speculate that this is exactly the point and that the parliament is thereby strive to “thwart… Trump’s plans for Iran.”

At the same time, conservative commentators and news outlets warn that the Iranian government is also attempting to use the last days of the Obama administration to exploit its more conciliatory foreign policy and shore-up the gains that Tehran has acquired from the nuclear deal. In an editorial at the Washington Post, Jennifer Rubin accused the outgoing administration of making “one final blunder” as part of a pattern of “serial concessions and excuse-making for the sake of ‘preserving’ the deal.”

She was referring to the Obama White House’s approval of a plan for Iran to receive 116 metric tons of natural uranium from Russia in exchange for Russia taking excess stockpiles of Iranian heavy water, the amounts of which are capped under the nuclear deal. The new arrangement was detailed by the Associated Press, and critics observe that the newly acquired uranium, if enriched to weapons grade, would be enough for Iran to construct 10 nuclear bombs.

Rubin characterizes that arrangement as the Obama administration helping Iran to violate and profit from the nuclear deal, as opposed to being held truly accountable by it. Critics of the administration took umbrage with the news late last year that Iran had exceeded heavy water limits for the second time since the deal went into effect, and had suffered no consequences in either instance but was in the first instance invited by the White House to sell the surplus to the US.

In spite of this and other perceived concessions to the Iranians subsequent to the nuclear deal, Tehran has made a habit of accusing the US of violating the “spirit” of the deal by continuing to enforce sanctions that are separate from the nuclear issue and by doing too little to encourage Western investment in the country. These accusations resurfaced on Tuesday, along with demands for “compensation” from the US following congressional reauthorization of the Iran Sanctions Act, which would have otherwise expired last month.

The Washington Free Beacon reported that alongside this demand for compensation, Iranian Foreign Ministry spokesman Bahram Qasemi threatened his countries retaliation against the US, as through the restarting of work on nuclear powered submarines and other weapons. Iranian officials may hope that such threats will elicit last-minute concessions from the Obama administration, which would possibly be motivated by fears that the nuclear deal itself would be in greater peril following such measures.

But at the same time, that agreement may already be imperiled by the transition from the Obama administration to the Trump administration, as the incoming president has described the agreement as one of the worst ever negotiated, and has shown an interest in cancelling or renegotiating it. And there are clear signs that Tehran is aware of the danger of losing the benefits it acquired under the deal, and that it is consequently considering a shift in policy, away from the bold demands for concessions that have characterized the past year and a half.

Along these lines, the Wall Street Journal reported on Tuesday that Iran had finally moved to reduce its stockpile of enriched uranium below the 300 kilogram cap set by the Joint Comprehensive Plan of Action. The parties that are participating in that agreement have met to discuss the prospects for cleaning up the mothballed uranium enrichment facility at Isfahan, which is estimated to contain 100 kilograms of material that is not currently being used.

However, even Iran’s discussion of these plans have been couched in defiant terms, with Deputy Foreign Minister Abbas Aragchi declaring that the removal of uranium from Isfahan will immediately allow Iran to enrich more material. But such commentary may raise the hackles of US critics and increase the likelihood of confrontation following Trump’s inauguration next week, after which he will be free to work with a strongly Republican-controlled Congress that strongly agrees with his perception of the Obama administration’s weakness in the face of apparent Iranian violations.