The ICC's chief prosecutor, Fatou Bensouda, speaks to reporters on May 3, 2018, in Kinshasa, Congo. (John Wessels/AFP/Getty Images)

Judges at the International Criminal Court (ICC) recently rejected Chief Prosecutor Fatou Bensouda’s request to open an investigation into alleged U.S. war crimes in Afghanistan. President Trump and National Security Advisor John Bolton — two of the ICC’s staunchest opponents — couldn’t be happier.

For years, Trump and Bolton have expressed a deep antipathy to the Court, asserting “the threat it poses to American national sovereignty.” Accordingly, the administration has threatened to sanction ICC personnel. The State Department even revoked the prosecutor’s visa earlier this month.

Are Americans as hostile to the ICC as the Trump administration? No. But as my research shows, public support for the ICC is hardly unanimous either, and sensitive to how the ICC’s work is described.

What is the ICC?

Established in 1998, the ICC is the first permanent international criminal court to prosecute war crimes and crimes against humanity. Previously, international criminal justice was delivered as needed — for example, at the Nuremberg trials in Germany following World War II or the International Criminal Tribunal for Rwanda, following the Rwandan genocide. The U.S. was a major player in the creation and implementation of both these courts. However, the U.S. has resisted the ICC because the Court could prosecute U.S. citizens.

Here’s how I did my research

In July 2018, I conducted an online survey of 1,020 American adults. As part of the survey, I included an experiment in which participants were randomly assigned to four groups. In each group, participants read an argument about the potential consequences of the U.S. joining the ICC.

The first group read a human rights argument that included this excerpt:

The U.S. has long been a defender of the international investigation and prosecution of serious crimes […] If the U.S. were to join the ICC, the U.S. could promote American democratic values, such as accountability and human rights, by helping the Court to investigate and prosecute individuals alleged to have committed serious crimes.

The second group read a national interest argument that included this excerpt:

The U.S. military has long been engaged in many different places around the world. And, there is opposition to U.S. involvement in some of these contexts. If the U.S. were to join the ICC, the Court could unfairly target U.S. leaders and military personnel for political reasons.

The third group read both arguments. The fourth and final group didn’t read either argument.

Everyone was then asked how much they agreed or disagreed that the U.S. should become a member of the ICC.

Americans are divided on the ICC, but opinions are sensitive to arguments

Among people who didn’t read either of the two arguments, a majority — 56 percent — somewhat or strongly agreed that the U.S. should become a member of the ICC. This lines up with recent polls conducted by the American Bar Association.

The different arguments for and against the ICC mattered. The human rights argument increased support: About 65 percent in this group agreed the U.S. should join the ICC. The national interest argument had the opposite effect: Only 42 percent of this group wanted to join the ICC.

When the two arguments were put together, the national interest argument appeared more powerful. Among the group who read both arguments, 48 percent agreed that the U.S. should join the ICC.

Survey participants were then asked about the factors behind their opinion. As expected, the different arguments that people read influenced the answers they gave. Most people who read the human rights argument and supported joining the ICC cited the U.S.’s potential influence on the ICC and human rights globally. Most people who read the national interest argument and opposed joining the ICC cited the ICC’s potential anti-U.S. bias.

What people’s opinions about the ICC mean

To be sure, one challenge of surveying people about the ICC is that many are not familiar with it. In my study, half of participants had no prior knowledge of the ICC — and it is likely that even those with some knowledge aren’t deeply familiar with the Court. So, as other scholars have noted, people’s views may have been susceptible to change on this issue. Different arguments, and especially cues from partisan political leaders, could change opinions in different ways than I examined in this study.

Moreover, it’s important to note that Americans’ feelings about the ICC may not translate into any actual political action. It is likely not central to how Americans vote, for example. So even if many Americans say that they support the ICC, this may not change U.S. policy and lead the U.S. to join the ICC.

What does this mean for the ICC’s future?

If American support for the ICC is not strong enough to compel U.S. policy makers to join the Court, could the ICC find a way to court more support? My research shows that people are most likely to support the ICC when they believe international organizations are effective and unbiased.

Thus, the ICC may be able to develop public trust — in the U.S. and beyond — by demonstrating effectiveness and impartiality. This could be accomplished by completing — rather than dropping — cases and expanding the subjects of investigation.

But, for now, the jury of public opinion is out.

Kelebogile Zvobgo (@kelly_zvobgo) is a PhD candidate in political science and international relations at the University of Southern California.

Survey participants were recruited through Amazon’s Mechanical Turk (MTurk) — a useful and inexpensive platform for fielding surveys. Public opinion researchers are divided on the acceptability of opt-in internet surveys. But if carefully executed, the results of internet surveys can be just as accurate as the results of telephone surveys. While participants recruited through MTurk do not perfectly represent the U.S. population, studies using MTurk have successfully replicated the results of studies using a nationally representative sample.