On entering office last week, President Joe Biden was greeted by an in-tray unprecedented in US history: a global pandemic that has already claimed 400,000 American lives, the worst economic crisis since the Great Depression, and the repercussions of a violent insurrection orchestrated by the outgoing President. Yet Biden has also undertaken to restore US global leadership following the unilateralism of the Trump years. There would be no more powerful way of doing that than by taking up the plight of the estimated 415 million children – one in six – who currently live in war zones.

Not since 1945 have so many children been subjected to such widespread violations of their human rights in areas of conflict. Despite calls by UN Secretary-General Antonio Guterres for a global ceasefire to focus on defeating Covid-19, children continue to be killed, raped, abducted and recruited to fight on an alarming scale. In recent months, at least 83 children have been killed in the Democratic Republic of the Congo’s Ituri province; more than 300 boys were abducted from their school in northwest Nigeria; eight children were assassinated in a suspected Boko Haram suicide bomb attack in northern Cameroon; and starvation has been employed as a weapon of war in Yemen, where millions of children are now on the brink of famine. Yet the perpetrators of such atrocities rarely face justice.

Biden has already signalled a desire to put children’s rights at the forefront of his Presidency. In his first 10 days in office, he has pledged to set up a process to reunite migrant children separated from their families at the US border, and put forward legislation to create a path to citizenship for so-called Dreamers, undocumented immigrants brought to the US as children. Biden’s American Rescue Plan includes pathbreaking proposals to dramatically cut child poverty through an expansion of the child tax credit. Could he also rally the international community to end the war on children?

The good news is that the blueprint already exists. In 2017, former UK Prime Minister Gordon Brown commissioned the Inquiry on Protecting Children in Conflict, a review of the adequacy and effectiveness of the international law framework governing the protection of children in war. Authored by a team led by British barrister Shaheed Fatima QC – and drawing on the input of an advisory panel of eminent international lawyers, activists and military advisors – the Inquiry’s report concludes that the international system of rules designed to uphold the rights of civilians in war is failing to protect children.

The report calls for immediate reforms, including giving schools the same protection as hospitals, making clear that a denial of humanitarian access will always be unlawful where it may lead to the starvation of civilians, and obliging states to take measures to prevent sexual violence against children. Yet even where the law provides adequate protection, it is being undermined by a systemic lack of compliance and accountability. To tackle this culture of impunity, the report urges renewed efforts to secure more widespread ratification of existing accountability mechanisms, including the Third Optional Protocol to the Convention on the Rights of the Child and the Rome Statute of the International Criminal Court.

The report’s principal recommendation is for the creation of a single international instrument that combines existing legal protections for children in armed conflict, buttressed by an international institution empowered to monitor and adjudicate the implementation of that instrument. These initiatives – which would clarify and simplify the law, as well as enhancing accountability for violations – could be incorporated within the existing architecture of the UN Convention on the Rights of the Child.

In his Inaugural Address, Joe Biden vowed to ‘repair our alliances and engage with the world once again’ and that the US would be a ‘strong and trusted partner for peace, progress and security.’ Biden has already overturned a number of executive orders signed by President Trump, including by re-entering the Paris Climate Agreement and the World Health Organization, and has promised to rejoin the Iran Nuclear Deal in his first 100 days in office. Yet Biden is unlikely to be satisfied with reversing the damage done by the Trump administration. He will want to reassert US moral leadership by advancing his own positive foreign policy agenda – and leading an international effort to end atrocities against children in war should be a central pillar.

Historically, the protection of children has been viewed not only as the cause most likely to secure cooperation across borders, but also as a means of transforming international relations. When states unite around universally appealing causes – such as the rights of children – they build goodwill that makes cooperation in other, more controversial, areas most likely. Eglantyne Jebb, the founder of Save the Children, once said that ‘every generation of children offers mankind the possibility of rebuilding his ruin of a world.’ By championing the human rights of children in conflict, President-Elect Biden can make the case for international cooperation we as rebuild ours.