Twenty years ago today, the international community achieved what had seemed impossible. Following negotiations over seemingly endless days and nights in Rome, governments from all around the world agreed to create the International Criminal Court (ICC): a permanent court to prosecute those most responsible for the worst crimes. Following decades of Cold War inaction, the UN secretary-general announced the end of the era of impunity. Victims of atrocities finally had an institution to turn to, and even the most powerful were to be accountable to the law.

Today, the ICC is no longer simply an ideal we are striving towards. It is a functional body and active in more than 20 states in all regions. Unlike a domestic court, where success can be measured by the number of prosecutions, trials and convictions, the ICC’s impact is more complex. The court only steps in if the national judiciaries are unwilling or unable to investigate and prosecute. Its watchdog role has helped pressure governments to take steps to bring those responsible for atrocities to account and to deter crimes in the first place. The court has broken new ground in establishing sexual violence as a weapon of war, helped trigger the release of many child soldiers, and made clear that destroying cultural heritage will be prosecuted as a war crime. Last December, States Parties to the Rome Statute demonstrated their confidence in the ICC by activating its jurisdiction over the crime of aggression: for the first time since the trials in Nuremberg and Tokyo, the leaders of states can be held to account for the illegal use of force in an international court.

Nevertheless, serious challenges remain. Even where the ICC has issued arrest warrants, states have been reluctant to carry them out, regardless of their legal obligation to do so. The court’s Achilles’ heel remains the lack of enforcement of the court’s orders. The outstanding arrest warrant against President Omar al-Bashir of Sudan, issued in 2008, is the prime example.

The court has also been criticised for its alleged Africa bias. Such criticism conveniently overlooks that, in most cases, African governments had requested the court’s help. ICC judges are on the brink of deciding whether to open investigations into crimes in Afghanistan, and the ICC prosecutor is looking into events in Palestine and Ukraine. As it furthers its reach, it should not be at all surprising if the attacks on the ICC become more frequent and forceful.

Calls are mounting on the UN Security Council to refer horrific violations outside the ICC’s jurisdiction to the court, such as in Myanmar and Syria. But some permanent council members simply do not want to mandate the court to investigate other situations, as accountability is not high on their agenda – sometimes due to their own national interests. All of this affects the credibility of the international legal order at a time when international organisations are under attack from populists, nationalists and those who want to roll back the achievements of multilateralism.

The creation of the ICC and its broad membership – there are 123 countries at present – is the most tangible contribution to a law-based world order over the last few decades. At a time when impunity for atrocity crimes continues unabated in many situations and respect for the most basic rules of warfare is being undermined, support for the court is more important than ever. History has taught us many terrible lessons about what happens when our international legal order does not hold up.

The ICC is the embodiment of a world in which I want to live and serve. Twenty years after its creation, it is our collective responsibility to protect and strengthen the ICC and fight for victims against those who would rather leave justice behind because it can become politically inconvenient.

We cannot take the existence of the ICC for granted today, and I, for one, do not want to imagine a tomorrow without it. For this reason, I implore leaders from all countries of the globe to cooperate with, support, and, when necessary, defend the ICC.

The views expressed in this article are the author’s own and do not necessarily reflect Al Jazeera’s editorial stance.