A 21-year-old Russian soldier pleaded guilty in a trial in Kyiv on May 18, 2022, for shooting a Ukrainian man in the head after Russia invaded Ukraine in late February 2022.

It marked the first trial of a Russian soldier for the war in Ukraine, as allegations mount of Russia committing war crimes – a broad category under international law that includes targeting civilians during conflict.

Ukraine is investigating more than 10,700 potential war crimes, involving more than 600 Russian soldiers and government officials. But there is a large gap between trying an individual sergeant for war crimes and holding Russian leaders themselves accountable for crimes committed during the war.

A lesser-known international crime, called the crime of aggression, could provide a pathway for prosecuting Russian President Vladimir Putin. This crime punishes the illegal invasion or use of force against another country. Only the leaders of the country that started a war can be held responsible for this crime.

Philippe Sands, a well-known international legal expert, has called a crime of aggression case against Putin “a slam dunk.”. This is because there is no legal justification for Russia invading Ukraine. But this legal option is complicated and would likely require forming a new international tribunal – a court set up to specifically investigate and charge people for violating international law.

And as an international lawyer, I know the biggest challenge to holding Putin accountable is not legal, but political. Setting up a special court would require a large political commitment by countries across the globe to follow through on the charges – and it would require a lot of money.

Understanding crimes of aggression

The crime of aggression, formally known as “crimes against the peace,” is generally defined as waging an aggressive war without legal justification.

This crime was first prosecuted at the post-World War II Nuremberg and Tokyo tribunals, which were established temporarily between 1945 and 1948. Thirty-one German and Japanese political and military leaders were convicted of these crimes, including Nazi Deputy Fuhrer Rudolf Hess.

There is little question among international lawyers that Russia’s invasion of Ukraine is an ongoing crime of aggression.

It’s an easier charge than other war-related crimes to level at a national leader. Charging Putin with war crimes would require substantial evidence – like witness testimony or intercepted communications – to prove that Putin planned, directed, knew of or should have known of specific attacks against civilians.

The crime of aggression, on the other hand, is intended for heads of states like Putin and their inner circle. Legal experts have drafted a model indictment against Putin. Many legal observers believe that there would be enough evidence to find Putin guilty of this crime and imprison him.

Not a panacea

Since the 1940s convictions, no one has been prosecuted internationally for crimes of aggression. One reason is that the International Criminal Court – an independent international court based in the Hague, Netherlands, that investigates genocide and war crimes – was not established until 2002. Before then, there was no clear place to prosecute this crime.

International lawyers also did not agree on an exact definition of crimes of aggression for the court until 2010. Russia has not joined the court. This means the court does not have legal power to independently prosecute Putin’s invasion of Ukraine.

The United Nations Security Council could also refer this case to the court. But as a permanent member of the Security Council with veto powers, Russia would block any attempted referral. Given the limits of the International Criminal Court in this case, a number of legal experts are discussing other pathways.

A new court

Most international experts say that the best option is a new international tribunal, separate from the International Criminal Court. Such tribunals are often set up with a narrow focus of war crimes from a particular conflict or atrocity. They are usually established through the United Nations.

That is because trials in national courts in Ukraine or another country – which recognizes the crime of aggression in their national laws – face various legal and political barriers. Some experts also say that a domestic court lacks the legitimacy of an international trial.

Another option is a hybrid – both international and national court – stemming from an agreement between the U.N. and a country. But legal restrictions in Ukrainian law, for example, make this difficult because the country’s constitution has specific language that could block a hybrid or special court.

The Parliamentary Assembly of the Council of Europe, a human rights organization that has 47 European countries as members, has called for a new international criminal tribunal, which would be based in Strasbourg, France, and would investigate and prosecute Russian leaders for crimes of aggression. The temporary tribunal would have the power to issue an alert to police worldwide to arrest Putin or other Russian leaders whom prosecutors are charging with crimes.

Establishing a new court, though, would take time and a large amount of money. While there are big differences in the various costs of international or hybrid tribunals, prior court processes have cost between $10 million to $15 million per defendant.

International and hybrid courts, such as those that were set up to address conflict in Sierra Leone, are usually funded by wealthy countries like the United States and the United Kingdom.

No end in sight

As the Ukraine war and reports of war crimes continue to unfold, some experts warn against placing too much emphasis on any one kind of legal process for prosecuting Putin.

Ultimately, the barriers to arresting Putin in a foreign country and getting him into any foreign courtroom remain high. Putin is unlikely to leave Russia and risk arrest, and his tight control over Russia at this point also makes it unlikely that he would be turned in by Russian police.

Although it is possible to hold a trial without a defendant present, many human rights experts strongly object to this practice.

And one of the most substantial critiques of establishing a special tribunal for Russia’s aggression is the challenge of selectivity – why this situation gets investigated and prosecuted internationally and why others, such as the U.S. invasion of Iraq, do not. But this is not a new challenge for international law and justice.

Once set up, an independent tribunal is beyond the political control of the countries that establish it.

To date, no head of a state whose country is a permanent member of the U.N. Security Council has been tried for the crime of aggression. This would open an important new chapter in modern international justice that would follow a complicated, uncertain course.

In explaining the reasons for Russia’s unexpected military weakness in Ukraine, few have expressed it better than “The Economist.” The magazine noted “the incurable inadequacy of despotic power” and “the cheating, bribery and peculation” that is “characteristic of the entire administration.”

Peculation means embezzlement. It is a word rarely used nowadays; these words were in fact published by “The Economist” in October 1854, when Russia was in the process of losing the Crimean War.

But they might just easily be about Russia today, under Vladimir Putin, and the mess of its invasion of its far smaller neighbor. Rarely have the pernicious effects of authoritarianism and endemic corruption been so vividly on display.

Indeed Ukraine’s National Agency on Corruption Prevention has cheekily thanked Russian officials for making “it much easier to defend democratic Ukraine” by embezzling “what should have gone to the needs of the army.”

How corrupt is Russia?

Of the world’s 20 major economies, Russia rates the worst on corruption. In 2021, the respected Corruption Perceptions Index compiled by anti-corruption body Transparency International scored Russia 29/100, alongside Liberia, Mali and Angola. This made it the 44th most corrupt nation on the index. (South Sudan was most corrupt, scoring 11/100, and Denmark the least corrupt, on 88/100.)

To be fair, Ukraine’s score isn’t much better, having gone though a similar post-Soviet privatization process that delivered immense wealth to a few oligarchs. Its 2021 corruption score was 32/100.

But President Volodymyr Zelenskyy has made tackling corruption a central policy, and Ukraine is improving on the index – unlike Russia. Ukraine also has some clear advantages for further improvements.

The U.S. organization Freedom House gives Ukraine a democracy score of 39.3%, compared with 5.4% for Russia. Transparency International rates Ukraine’s democratic processes as “generally free and fair”. It considers efforts in recent years to tackle corruption as slow and flawed, but nonetheless genuine and substantive.

Russia’s rule of thieves

Putin’s Russia, on the other hand, is described by Transparency International as a kleptocracy – a government of thieves. Putin himself is estimated to have accrued a fortune of US$200 billion, making him (unofficially) the world’s second-richest man, after Elon Musk.

Putin’s wealth accumulation methods are relatively straightforward. According to Bill Browder, a fund manager specializing in Russian markets, having Mikhail Khodorkovsky – then Russia’s richest man – sent to prison in 2005 proved particularly fruitful:

After Khodorkovsky’s conviction the other oligarchs went to Putin and asked him what they needed to do to avoid sitting in the same cage as Khodorkovsky. From what followed it appeared that Putin’s answer was “50%” […] for Vladimir Putin personally.

Much of Putin’s fortune is squirreled away in foreign bank accounts and investments, as revealed by the Pandora Papers. But he also enjoys material comforts such as a palace on the Black Sea reputed to have cost about US$1 billion – paid in part out of a government program meant to improve health care.

Stealing from military budgets

Money supposed to be for Russia’s military capability has also been plundered. For example, defense minister Sergei Shoigu lives in an $18 million mansion – not bad for someone supposedly on a government minister’s salary.

A typical pattern has been to award contracts to companies owned by cronies, who then provide shoddy products and pocket huge profits. Food and housing in the Russian military is said to be worse than being in prison. Russian soldiers sent to invade Ukraine have been given rations years out of date.

This has created a “Potemkin military” – all show and little substance – according to Andrey Kozyrev, Russia’s foreign minister from 1990 to 1996:

The Kremlin spent the last 20 years trying to modernize its military. Much of that budget was stolen and spent on mega-yachts in Cyprus. But as a military advisor you cannot report that to the President. So they reported lies to him instead.

Social distrust runs deep

It should be no surprise, therefore, that Russia is a deeply distrustful society. This has been measured by global surveys such as Lloyd’s Register Foundation World Risk Poll and the Edelman Trust Barometer. This distrust has been a hallmark of the Russian military’s performance in Ukraine.

Western military organizations emphasize empowering individual units to show initiative when plans go wrong. In marked contrast, the Russian military structure, like the state, is based on command and control, with little faith or trust in troops.

In particular Russia’s conscription-dependent army lacks non-commissioned officers. These senior enlisted personnel train and supervise troops, and often take over leadership of smaller units in wartime.

This helps explain the high number of senior Russian generals killed on the front line in Ukraine – 12 at last count. Typically, generals manage battlefields from a safe distance. But, as a recent report from The Economist has noted:

Morale has been low, logistics poor and casualties high. And that seems to have forced the generals to get their boots muddy.

And also put themselves within range of Ukrainian snipers and missiles. This war, which the Russians expected would be over in days, has just entered its fourth month. It’s possible the Russian military can learn from its strategic and logistical blunders, and still win the battle for the Donbas area. But, unlike many Russian officers, general corruption and general distrust remain on the battlefield.