Clockwise, from top left: Georgians hold candles during a remembrance ceremony in Gori, west of Georgia’s capital, Tbilisi, a year after the August 2008 war between Georgia and Russia over the breakaway region of South Ossetia. / Relatives hold pictures of their beloved during a March 6, 2009 march in Bogota against the “false positive” killings and enforced disappearances allegedly carried out by Colombian authorities between 2002 and 2008. / People hold a banner reading “We will never forget the dead, the missing, the wounded and the raped women of September 28, 2009” in Guinea’s capital, Conakry on September 28, 2016, marking the seventh anniversary of the Guinean security forces attack on a peaceful demonstration at a stadium that left 150 people dead and dozens of women raped. / Daoud Mousa, father of Baha Mousa who died in 2003 at the age of 26 while in the custody of British soldiers in Iraq, shows photographs of his son and family to the media as he arrives at a July 28, 2004 London court hearing on human rights violations in Iraq. 

© 2008 David Mdzinarishvili/Reuters / © 2009 MAURICIO DUENAS/AFP/Getty Images / © 2016 CELLOU BINANI/AFP/Getty Images / © 2004 Graeme Robertson/Getty Images

Activists and victims of some of the worst crimes committed in West Africa sat down together in Banjul, Gambia recently to talk about how to bring to justice more people responsible for these crimes.

We heard from people from Côte d'Ivoire, Guinea, Gambia, and Liberia at a conference organized by Africa Legal Aid. The speakers described intense frustration with their governments' inadequate political will and insufficient resources to hold to account those responsible for war crimes, crimes against humanity and torture.

But we also heard from activists that progress is possible. The conviction of Hissène Habré in Senegal for crimes against humanity, rape and torture in Chad after a 17-year grassroots campaign stands out. Prosecutions of people from Sierra Leone's three warring factions during the country's civil conflict at the United Nations-backed Special Court for Sierra Leone was a major achievement.

And the conclusion of an investigation by a panel of Guinean judges into that country's 2009 stadium massacre, which paves the way for trials of those responsible for killings, rapes and other crimes, gives hope for justice in the future.

A new Human Rights Watch report looks at the role that the International Criminal Court (ICC) can play to catalyze domestic trials.

From the very beginning, the people who worked to make the ICC a reality saw the court as part of a system deeply rooted in and connected with national justice. While the ICC needs to be ready to act when there are no other avenues for credible trials, it was set up as a court of last resort to try cases of genocide, war crimes and crimes against humanity only when they cannot be tried by domestic courts.

National authorities have the primary responsibility to ensure that victims get justice. Where possible, trials at – or close to – home will have more impact and resonance than trials in distant courthouses. As the court's treaty, the Rome Statute, nears its 20th anniversary in July, the court and its member countries should fully support this vision.

In fact, because governments can avoid cases going to the ICC if they themselves act, the ICC prosecutor's office has leverage to encourage and support governments to deliver fair justice themselves, particularly while it conducts preliminary examinations to determine whether investigations by the ICC are needed. Indeed, the ICC prosecutor has recognized this opportunity and seeks to do that where it is feasible.

In our research, we looked at four countries that have or had ICC preliminary examinations: Colombia, Georgia, Guinea and the United Kingdom.

We found that ICC preliminary examinations can encourage national justice processes, although expectations about what the ICC prosecutor's office can achieve need to be realistic.

Among the four countries, Colombia is the only place where relevant prosecutions have moved ahead, and even there, too little progress has been made in cases against senior military officials.

In all four countries, the ICC prosecutor's office has contributed to at least some progress, most significantly in Guinea.

The ICC prosecutor's intense engagement with Guinean authorities – including more than a dozen visits to the country and identifying specific investigative steps needed, like interviewing key witnesses – encouraged progress when the justice effort looked like it might stall. Victims' associations, UN experts, and others also played a key role. While trials have yet to start, the progress in Guinea has surpassed the expectations of many of the people we interviewed.

The ICC prosecutor should make the most of this kind of opportunity, including through setting clear benchmarks for national investigations, effective engagement with civil society groups, and providing analysis to help national justice systems figure out how to move ahead. It won't always work, and, as in Guinea, the office needs partners, but given the stakes for expanding victims' access to justice, it is worth the effort.

The ICC will not always be in the picture. In Liberia, for example, the crimes at issue largely took place before the ICC's mandate began so the court's prosecutors do not have the authority to investigate those crimes. While the prosecutor's office lacks the same leverage it has in Guinea, in can still share its expertise to support national prosecutions, for example on issues such as witness protection.

West Africa has been a crucial supporter of justice in many ways, including for the creation of the ICC and defending the court from unjustified attacks at the African Union. But the compelling stories we heard at the Banjul conference from victims who still await justice showcase the need for greater action by governments in the region to prosecute grave crimes.

Our experience documenting abuses committed around the world over more than two decades reinforces that lack of justice often fuels further abuses, and the victims and activists who came together highlighted the need for perpetrators to be held to account wherever grave crimes are committed.