IN LATE January, just nine days after President Donald Trump’s inauguration, Iran tested a new medium-range ballistic missile – the Khorramshahr. The missile has a range of 3,000-4,000 km, which can reach all of Western Europe and can carry a nuclear payload. This test was the latest in a string of Iranian ballistic-missile tests that have been carried out since the nuclear deal (JCPOA) was announced in July 2015.And, it was their first test of the Trump administration, which has not yet clarified its Iran policy but has already projected that it is not happy either with the JCPOA or with Iran’s ongoing provocations since the deal was announced.The immediate question that arises following the missile test is whether it is prohibited by international agreements. As far as the nuclear deal itself is concerned, none of Iran’s missile tests have constituted a violation for the simple reason that ballistic missiles are not covered by the deal even though, as the delivery mechanism for carrying a nuclear warhead, they are intimately connected to a nuclear weapons program.The omission of ballistic missiles from the JCPOA was the unfortunate result of the US unwisely caving to Iran’s demand not to include them in the nuclear talks, in effect acquiescing to Iran’s narrative that such missiles are “non-nuclear.”Indeed, one of the first concessions to Iran, before formal negotiations between the P5+1 and Tehran commenced, was that ballistic missiles would be off the table. Because of this concession, the only reference to Iran’s missile program is currently included in UN Security Council Resolution 2231, which endorses the JCPOA. But compared to Resolution 1929, which was still in effect in October 2015 when Iran conducted its first post- JCPOA ballistic-missile test, Resolution 2231 only “calls upon” Iran to desist from these activities, rather than prohibiting them.Moreover, the new resolution includes changed wording that opens space for Iran to claim that the test is not covered by the resolution.Rather than targeting missiles “that can carry a nuclear payload,” Resolution 2231 refers to missiles “designed to” carry a nuclear payload. Because Iran denies any past nuclear weapons work and any future plans in this regard, it has argued that no missile developed in Iran could possibly have been designed to carry a nuclear warhead.The Trump administration is not buying Iran’s excuses ‒ and for good reason: Iran’s attempt to explain away any wrongdoing through such legalistic gymnastics rests on very shaky ground.The reality that Iran refuses to acknowledge is that it actually did work on a military nuclear program in the past and it never demonstrated that it left those ambitions behind. Iran is a proven violator of the NPT, and, yet, it denies any wrongdoing. Under these circumstances, there is no reason to believe that Iran will never equip its nuclear- capable missiles with a nuclear warhead and, therefore, these missiles could very well have been (and most likely were) designed with this in mind.THE EXPERIENCE of the past year and a half has seen the Obama administration refrain from any pushback against Iran’s repeated provocations, belligerence and even some violations of the JCPOA itself, which has only served to embolden Iran and increase its leverage vis-à-vis the United States. With no reaction from the US – including firmly setting the record straight about Iran’s past nuclear weapons program and undermining Iran’s false narrative – there is little doubt that Iran would have continued to test any and all missiles with relative impunity.But, if no Iranian missile could possibly meet the criteria set by Resolution 2231, what was the resolution originally meant to curb? On the basis of its very different interpretation and approach, the Trump administration responded to the latest missile test quickly and firmly. It immediately called an emergency meeting of the UN Security Council to discuss the test, and National Security Adviser Michael Flynn (who has since resigned) then issued a statement that “put Iran on notice” while informing the Iranians that the US will no longer be turning a blind eye to their provocations. Sanctions were quickly imposed on 25 Iranian individuals and companies involved in Iran’s ballistic missile program and with connections to terrorist activities. Later, it was reported that the US was considering naming the IRGC a terrorist group. Trump himself warned Iran’s President Hassan Rouhani that he “better be careful” with his words.Taking a closer look at Flynn’s statement, in particular, many were quick to criticize it as “bellicose bluster” that risked escalation with Iran.Such interpretations ignored the fact that the US was responding to Iran’s belligerence.Indeed, in light of ongoing Iranian provocations that have gone unanswered for far too long, Flynn’s statement was an appropriate and measured American response.Critics also complained that Flynn’s message was non-specific, not stating clearly what the administration would do. But nowhere is it set in stone that the best way to deter a state is by clarifying the precise conditions and consequences of their action. In fact, setting a clear red line could very well have been counterproductive because it could have easily set the new administration up for failure – which is precisely what happened to president Barack Obama in 2013 when he warned Syrian President Bashar Assad that using chemical weapons would elicit an American military response. The Trump administration’s deterrent message was most likely intentionally non-specific.PUTTING IRAN on notice puts Tehran off balance – a desired result. It means Iran must be very careful because it does not know what action will trigger which response. From initial Iranian reactions, it seems that the deterrence is working: They are not sure what Trump might do, and Iranian media have reflected advice to Iran’s leaders not to do anything that might give Trump an excuse to attack.Moreover, it was reported in early February that Iran abruptly removed from the launch pad a missile being prepared for launch. It was a Safir missile, derived from the Iranian Shahab 3, which Iran had, on several occasions, used as a launch vehicle for its satellites, indicating technology for a long-range intercontinental missile.Instead of the Safir, the next day, Iran tested a different missile – a short-range, surface-to-air missile, called Mersad ‒ that Iran most likely calculated would arouse less opposition. Coming on the heels of the removed Safir, the fact that Iran tested the Mersad is not an indication that Iran is ignoring Trump’s warnings. Quite the opposite: it could very well indicate that Trump’s deterrent message had been received and had affected Iran’s decision.On the domestic US front, a string of controversial decisions by the Trump administration – the immigration ban, in particular – have caused an uproar in the United States and around the world.Trump’s detractors seem hard-pressed to find words strong enough to express their extreme displeasure with everything he has done so far. For many, any response to Trump administration policy that is not total rejection is tantamount to support for Trump, or worse, identification with the new president.The tendency to fuse support for a specific policy with support for the policymaker should be resisted. Americans (and the rest of the world) must learn to differentiate between good and bad policy and recognize good policies, even if they have strong reservations about the administration that forged them.To be clear, this latest missile episode was not sparked by President Trump challenging Iran. In the face of Iran’s ongoing defiance and lack of cooperation, the response to its dangerous missile activity was long overdue.Some media supportive of former president Obama have criticized Trump for challenging Iran, when it is now much stronger.A bizarre observation indeed because, if Obama had responded with the necessary determination to Iran’s provocations from the start, Iran would not have gotten stronger.It is, indeed, the absence of response that emboldens and strengthens Iran. If Trump were to continue in that vein, as Obama supporters suggest, the situation would only get worse. Provocations necessitate a firm response, which is what the Trump administration has finally provided. Dr. Emily B. Landau, a senior research fellow at the Tel Aviv-based Institute for National Security Studies (INSS), is director of the institute’s Arms Control and Regional Security Program.