New Study on Sanctions: Do Opposites Attract? Not in Foreign Policy.

9 April 2026, by Newsroom editorial office

Im Wörterbuch ist der Eintrag Sanktionen, auf Englisch Sanctions, mit pinkem Textmarker unterstrichen.

Photo: AdobeStock/Feng Yu

Sanctions are widely used as a tool of foreign policy. Whether they are imposed also depends on the backgrounds of the key decision-makers.

International sanctions are imposed less frequently when the political leaders involved have similar curriculum vitae. This is shown by a new study involving Dr. Jerg Gutmann of the University of Hamburg. Based on data from more than 150 countries, the study examined when sanctions were imposed between states during the period from 1970 to 2004—and whether these decisions are statistically correlated with biographical similarities among the heads of government involved.

For their analysis, the researchers combined information spanning several decades of international sanctions policy with a dataset documenting the professional and personal curriculum vitae of leading government officials worldwide. “We examined dozens of characteristics such as age, gender, education, professional history, military service, and political career paths of heads of state and government,” explains Dr. Jerg Gutmann. He conducts research on the rule of law and international conflicts at the Faculty of Law at the University of Hamburg and carried out the study together with Pascal Langer and Prof. Dr. Matthias Neuenkirch from the University of Trier.

For each pair of political leaders, the study measured the extent to which their characteristics and life experiences align. “Using this approach, we see, for example, a strong similarity between Gerhard Schröder and Vladimir Putin,” says Matthias Neuenkirch, illustrating the findings. “This pattern remains surprisingly stable, even when we use alternative statistical methods and account for different biographical characteristics.”

Biographical similarity as an influencing factor

The statistical analysis shows: The more the biographical profiles of political leaders from two countries resemble each other, the lower the probability that these countries will impose sanctions on one another. Compared to pairs of heads of state who are very similar, pairs who are very different impose sanctions more than three times as often. This correlation is particularly evident where governments can decide on sanctions autonomously without being bound by the joint decision-making procedures of inter- and supranational organizations, such as the United Nations or the European Union.

A pronounced effect is also found in sanctions justified by democratic or human rights objectives. In other words, politicians here appear to have significantly more discretionary authority. In security- or conflict-related contexts, however, the similarity of political leadership plays a lesser role.

The study builds on psychological research on the phenomenon of homophily and in-group dynamics. These studies assume that people with similar backgrounds often communicate more easily with one another, are more likely to develop trust, and therefore tend to resort to diplomatic means before allowing conflicts to escalate. Applied to foreign policy, this means that biographical similarity between heads of government increases the likelihood of resolving conflicts through negotiation rather than coercive measures.

Political Implications

The results suggest that international sanctions policy is more heavily influenced by personal factors than a focus on institutional procedures would suggest. For understanding foreign policy decisions, this means that the biographical composition of political elites should also be taken into account. “Overall, the study shows that foreign policy sanction decisions are influenced not only at the state level but also by the personal characteristics of political leadership. Anyone who wants to shape sanctions policy in an effective and transparent manner should give this dimension sufficient consideration,” says Gutmann.

The research group is now working to apply the measurement method used to more recent international politics and is collecting biographical information on political leaders beyond 2004, the last year covered so far.