Since the first world war, governments have increasingly used economic sanctions to achieve their international political objectives. Despite a century of experience, however, the rationale for such measures remains far from compelling.

Economic sanctions have become even more popular in recent decades. In the 1990s, for example, sanctions regimes were introduced at an average rate of about seven per year. Of the 67 cases in that decade, two-thirds were unilateral sanctions imposed by the United States. In fact, the great majority of sanctions are imposed by large countries against small countries.

In addition to targeting specific countries, the UN has also imposed sanctions on non-state entities such as al-Qaeda, the Taliban and, more recently, the so-called Islamic State.

But it remains highly doubtful that Iran will change its policies, let alone its regime, in the face of Trump’s sanctions. The simple truth about economic sanctions is that, though widely used, they often fail.

A comprehensive study of 170 20th-century cases in which sanctions were imposed concluded that only one-third of them attained their stated objectives. Another study estimates the success rate of sanctions regimes to be lower than 5 per cent.

Such a high failure rate suggests that governments often use flawed arguments to justify imposing sanctions. Seven misconceptions or fallacies stand out. Each needs to be debunked.

First, sanctions are justified as a gentler and more humane alternative to war. But this underestimates the potential for international diplomacy to resolve conflicts. And in reality, sanctions often pave the way for wars rather than averting them: 13 years of international sanctions against Iraq were followed by the 2003 US-led invasion, for example.

A second argument is that “if sanctions are hurting, they must be working”. But this criterion of effectiveness fails to define what would constitute success. Worse, it flies in the face of evidence suggesting that sanctions hurt large swathes of the civilian population. They stymie economic growth, undermine production and cause businesses to fail, resulting in higher unemployment.

Third, sanctions are often said to be “smart” and “targeted”. In practice, however, comprehensive economic sanctions are collective punishment. They squeeze the middle classes and impose a disproportionate burden on the poorest and most vulnerable, who are arguably the biggest victims of the very regimes that sanctions are designed to punish.

Fourth, some governments justify sanctions as a way to uphold and promote human rights. But evidence suggests that civil society groups and NGOs are generally among the biggest losers under sanctions.

By portraying sanctions as foreign aggression and economic warfare against their country, authoritarian regimes often accuse human rights activists of being allied with the enemy. From there, it’s a short step to a national security crackdown on such organisations.

Similarly, sanctions against Saddam Hussein’s Iraq in the 1990s led to the wholesale destruction of civil society there, helping to stoke the identity politics and sectarianism that continue to bedevil that country and the wider region.

A fifth claim is that sanctions are necessary and effective in bringing about regime change. The cases of South Africa and Zimbabwe notwithstanding, this is probably the weakest of the seven arguments – as the longevity of sanctioned regimes in countries such as North Korea, Cuba and Myanmar indicate.

Sixth, sanctions are said to weaken the targeted governments. But by worsening the business and investment climate, economic sanctions take their toll primarily on the private sector. If anything, power becomes more centralised as governments increasingly control supplies of strategic commodities, given the shortages they cause.

Finally, sanctions are supposedly effective in containing nuclear proliferation. Here, too, their record is demonstrably poor. Since the Non-Proliferation Treaty entered into force in 1970, four countries have acquired nuclear weapons: Israel, India, Pakistan and North Korea. Three of them did so while under sanctions.

Ultimately, the success or failure of economic sanctions is judged by whether they bring about regime change or change a government’s behaviour. Given the prevailing misconceptions about their rationale, it is not surprising – as we are likely to see again in Iran – that they so often achieve neither goal. What is more certain is that destabilising Iran will make the region more dangerous than ever.

Hassan Hakimian, director of the London Middle East Institute and reader in economics at SOAS, University of London, is a co-editor of Iran and the Global Economy: Petro Populism, Islam and Economic Sanctions. Copyright: Project Syndicate