We’ve been here many times before, but the result has never changed. Iran’s diplomatic intransigence is met with the threat and eventual passing of economic sanctions.Each time, the hope is that Iran will be convinced to enter into serious negotiations.This “dual-track” approach has yet to still Iran’s march toward nuclear weapons capability – yet we pursue this course in the absence of better options.The sanctions tool has been weakened by the lack of consensus in the international community, thus limiting the pressure levelled on Iran.Tired of the consensus obstacle, the European Union took a significant step on Monday by approving its own set of “comprehensive and robust” sanctions, incorporating – and substantially exceeding – those passed by the United Nations Security Council in June. The measures are indeed the strongest sanctions implemented by the EU and fill important gaps left by the UNSC resolution – particularly through the targeting of Iran’s energy sector. But are they enough to convince Iran to alter its behavior? If one believes that sanctions will thwart Iran’s nuclear course on their own, the outcome is likely to be disappointing. No set of sanctions, short of a universally enforced embargo, is likely to bring Iran’s program to an immediate stop – and the international consensus for such a forceful move does not exist, nor cannot it be expected in the near future.However, if the point is to ratchet up the pressure to get Iran to return to negotiations – this time in good faith – then the prospects for success are greater.The EU’s new sanctions will have an effect on the Iranian economy, and thus on the country’s leadership. By targeting Iran’s economic central core, its energy industry, EU sanctions will restrict the revenue stream that is funding the Iranian nuclear program.The prohibition against EU companies investing in new energy projects will hinder growth, and the ban against the sale of dualuse technologies will complicate the general maintenance of the sector.It is true that companies from other countries, notably from Russia and China, will fill the void. But securing replacement contractors will also come at a cost to Iran. Recognizing the decreasing number of firms willing to invest in Iran, Chinese companies have been known to demand more profitable rates of return. In other cases, Iran has been forced to accept inferior services and products from alternative sources.FURTHERMORE, THE blacklisting of individuals and entities in the Islamic Revolutionary Guard Corps will help restrict the very body in charge of Iran’s nuclear development.To sufficiently pressure them, a more comprehensive list will be needed; allied nations contemplating next steps in the effort to thwart Iran’s nuclear ambitions will undoubtedly turn their attention to filling out such a list in the weeks ahead.Neither the energy-sector restrictions nor IRGC blacklisting is likely to be crippling, but they will create strains on an already strained economy and pose challenges to a regime already at pains to respond to fundamental public needs.Absent cooperation from companies in the EU, a number of vital industries in the Iranian economy will be unable to procure necessary technical investments. Iran, in turn, will be hard-pressed to attain the energy-sector output to fulfil its revenue obligations in the annual budget – always a touchy political issue.Iran has, to this point, felt confident in its ability to withstand the fiscal effects of sanctions while it pursues its nuclear objective. Quite simply, Teheran has calculated that it would reach its goal of weapons capability before the international community can increase the economic pressure to the point that it would be intolerable.It has been buoyed by the reluctance of key international actors – notably Russia and China, and increasingly Turkey – to go along with further UNSC sanctions, to enforce them, and to go beyond them.The latest news from Brussels, however, seems to have seized Iran’s attention.Within hours of the sanctions’ approval by the EU Foreign Affairs Council, Iran reportedly offered to restart negotiations concerning a fuel swap “without conditions.”It will be wise for the EU, with its American and other international partners, to regard such a proposal with skepticism, in light of the long record of delays and broken promises that has defined Teheran’s approach to the international community on matters relating to its nuclear program. In the past, Iran has consistently used negotiations as a stalling tactic to allow its nuclear development to proceed apace.If the EU wants to be sure Iran will act in good faith, it must continue to expand the international consensus and deliver a clear message to Tehran: should a serious, productive dialogue not ensue, further action will immediately be taken.The EU has shown its intent to punish Iran for its intransigence. Now it must also prove its resolve.Indeed, the work has just begun.The writer is the program director of the AJC Transatlantic Institute in Brussels.