Who is a war criminal and who decides?

President Joe Biden on Wednesday categorically declared his Russian counterpart Vladimir Putin a “war criminal” over the ongoing battle in Ukraine, where Russian forces have bombed hospitals and maternity wards.

But declaring someone a war criminal is not as simple as just saying the words. There are definitions and established processes to determine who is and what punishment should be meted out.

The White House had refrained from applying the designation to Putin noting that this requires an international investigation and determination. After what Biden used the term, the White House press secretary, Jen Psakisaid the president “spoke from the heart” and she reiterated that there is a process to formally specify that determination.

However, at a popular level the expression has acquired a colloquial meaning as a generic term for someone heinous.

“It is clear that Putin is a war criminal, but the president is making a political statement on this.”said David Cranewho has worked on war crimes for decades and served as chief prosecutor of the Special Court of the UN for Sierra Leonewhich prosecuted the former Liberian president Charles Taylor.

Investigations into Putin’s actions have already begun. The United States and 44 other countries are working together to investigate possible violations and abuses, after the United Nations Human Rights Council approved a resolution to establish an investigative commission. There is another investigation under way by the International Criminal Court, an independent body based in the Netherlands.

“We are at the beginning of the beginning”said Crane, who now heads the Global Accountability Network, which works with the international court and the UN, among other organizations. On the day of the invasion, her group set up a special team to compile criminal information related to war crimes. Crane is also developing a prototype indictment against Putin. She predicted that an indictment against the Russian president could take place within a year. But these types of crimes do not prescribe.

Here’s a look at how this all works:

Who is a war criminal?

The term applies to anyone who breaks a set of rules approved by the rulers of the world and known as the laws of war. These rules govern how countries behave in times of war.

They were modified and expanded in the last century, based on the Geneva Conventions after the WWII and protocols added later.

The regulations are aimed at protecting people not involved in the fighting and those unable to continue fighting, including civilians such as doctors and nurses, wounded soldiers and prisoners of war. Treaties and protocols establish who can be attacked and with what kind of weapons. Certain weapons are prohibited, including chemical and biological agents.

What specific crimes make someone a war criminal?

The so called “serious violations” of the conventions constituting war crimes they include deliberate killings, as well as extensive destruction and appropriation of property not justified by military necessity. Other war crimes include the deliberate attack on civilians, the disproportionate use of force, the use of people as human shields and the taking of hostages.

The International Criminal Court as well prosecutes crimes against humanity committed in the context of “a widespread or systematic attack against any civilian population”. These include murder, extermination, forced relocation, torture, rape, and sexual slavery.

The most likely way for Putin could be singled out as a war criminal would be through the widely recognized legal doctrine of command responsibility. If commanders order or even know or are in a position to know about crimes and do nothing to prevent them, they can be held legally responsible.

What are the paths to justice?

In general, there are four ways to investigate and determine war crimes, although each has its limits. One is through the International Criminal Court.

A second option could be for the UN to shift its work on the investigative commission to a hybrid international war crimes tribunal to try Putin.

A third would be to create a tribunal or court to prosecute Putin by a group of interested or affected entities or countries.as the NATOthe European Union (EU) and United States. An example is the Nuremberg trials against the Nazi leaders after the end of World War II.

Finally, some countries have their own laws to prosecute war crimes. Germanyfor example, is already investigating Putin. The United States lacks such a law, but the Justice Department has a special section that focuses primarily on acts such as international genocide, torture, recruitment of child soldiers, and female genital mutilation.

Where could Putin be put on trial?

It is not clear. Russia does not recognize the jurisdiction of the International Criminal Court and would not hand over any suspects to that court based in The Hague, the Netherlands. The United States also does not recognize the court’s authority. Putin could be prosecuted in a country chosen by the UN or by a consortium of interested nations. But getting him there would be difficult.

Have other rulers been prosecuted in the past?

Yes. Since the Nuremberg and Tokyo tribunals after World War II, various leaders have been prosecuted for their actions in countries such as Bosnia, Cambodia and Rwanda.

former Yugoslav ruler Slobodan Milosevich was prosecuted by a court of the UN on Hague for fueling the bloody conflicts during the collapse of Yugoslavia in the 1990s. He died in his cell before the court could reach a verdict. His Bosnian Serb ally Radovan Karadzic and Bosnian Serb military leader General Ratko Mladic were put on trial and are both serving life in prison.

Taylor from Liberia was sentenced to 50 years after being found guilty of promoting atrocities in neighboring Sierra Leone. The former dictator of Chad Hissene Opens, who died last year, was the first former head of state to be found guilty of crimes against humanity by an African court. He was sentenced to life in prison.