Australia’s currency and stock market dropped in recent days due to the activities of a fifty-year-old pastor from North Carolina, who has a congregation of twenty-five.

In 2016, Pastor Andrew Brunson was arrested in the Turkish city of Izmir after being accused of spying and of supporting a thwarted coup. His arrest angered American evangelicals and prompted Donald Trump to impose sanctions on Turkish cabinet members and to double tariffs on its aluminium and steel. This added to jitters about Turkey’s economy, which, combined with the impact of recent sanctions on Russia, rippled through global markets.

The incident, aside from demonstrating the strange butterfly effects that can upset the markets, highlighted Trump’s penchant for sanctions, which have boomed since he took office and are disrupting both international economics and diplomacy.

Last year, Trump added 944 people or entities to the United States sanctions list, the most since the aftermath of the September 11 attacks. This year he is expected to add more than 1000.

Typically prone to excess, Trump is extending a trend that began during the Cold War. As advances in weapons technology make warfare riskier, even for nations with strong militaries, sanctions have become a popular tool.

Australia is no exception. Canberra’s sanctions regime often attracts little attention, but Australia currently has sanctions against eighteen countries in Africa, Asia, Europe and the Middle East, as well as on three organisations – Islamic State, Al Qaeda and the Taliban – and against people and entities with terrorist links. 

The list of individuals and firms subject to Australian sanctions includes 6009 entries, such as (to give two examples selected randomly): Mohamed Amin Mostafa, a forty-two-year-old Iraqi linked to Islamic State who is listed as living at Via della Martinella 132, Parma, Italy, and Sergey Yurievich Glayzev, a fifty-seven-year-old whose address is unknown and is designated as “Presidential adviser to President Putin. Publicly called for the annexation of Crimea.” 

Of Australia’s twenty-one sets of sanctions, thirteen implement United Nations Security Council measures. These include sanctions against Iraq, Somalia, Sudan, South Sudan and the Democratic Republic of the Congo. Australia also implements UN sanctions against North Korea, Iran and Libya, but adds its own. And Australia has its own sets of sanctions against Myanmar, Russia, Syria, Zimbabwe and the former Yugoslavia, though these have typically been developed in partnership with other concerned countries.

According to Australia’s sanctions legislation, the three aims of such measures are to punish international offenders, to encourage a change of behaviour and to affect the outcome of an international issue or conflict – for instance, by limiting arms sales. But there has long been debate about whether sanctions actually work. A well-known study, led by an American trade expert, of 200 sets of sanctions across the world between 1914 and 2008 found that about a third worked, though some critics dispute the finding and say the amount is as low as 5 per cent. 

In the decade since, there have been some positive signs that nations are becoming smarter about the development of sanctions. Sanctions from several major powers have become more targeted, particularly in relation to Russia. They may not have had their desired effect but, judging by alleged efforts to persuade the Trump campaign team to ease them, they are irking the Moscow elite. 

Some analysts believe that sanctions are more likely to succeed if they have limited goals – the release of prisoners, say, as opposed to regime change. Many also believe that sanctions tend to be less effective if they continue indefinitely, partly because the targeted country often finds ways to break them or seeks alternative trade partners. For example, Iraq’s Saddam Hussein notoriously flouted sanctions for years, sometimes courtesy of the Australian Wheat Board.

Despite the mixed success of sanctions, one of the main reasons for using them has been, as former British diplomat Sir Jeremy Greenstock told the BBC in 2010, “There is nothing else between words and military action if you want to bring pressure upon a government.”

Most analysts believe that international cooperation is a vital component of effective sanctions. Australia has traditionally followed this rule and, in rare cases when it helped to lead the effort to impose sanctions, such as after the coup in Fiji in 2006, it encouraged other nations to cooperate.

Trump, in typical fashion, is breaking the mould when it comes to sanctions. He has acted alone against Russia, Iran and now Turkey. This unilateralism makes US sanctions easier to breach. Worse, it adds a sense of unpredictability to the process – a consequence that not only affects global financial stability but also threatens to undermine confidence in the international sanctions regime, and the care with which targets are selected.

Australia, which has participated in the sanctions boom in recent decades, should encourage Washington to seek international solidarity before it adds to its list of targets. This will not only increase Australia’s confidence that it should enforce sanctions set by others but also make them more likely to succeed.