While nobody expects the Marshall Islands to force the three powers to disarm at Monday's hearing, the archipelago's dogged campaign at the International Court of Justice highlights the growing scope for political minnows to get a hearing through global tribunals.
All three are expected to argue that the Marshall Islands' claims are beyond the Hague court's jurisdiction and should be thrown out. But many activists and academics believe getting them into court is a victory in itself.
The island republic, a US protectorate until 1986 and home to just 50,000 people, was the site of 67 nuclear tests by 1958, the health impacts of which linger to this day.
“The success will be in putting the issue back on the agenda...This is as much as the Marshall Islands can hope for," said Dapo Akande, professor of international law at Oxford University.
“When the Marshall Islands goes to the ICJ, its equal with Britain and with India," Akande added.
“Big countries get dragged into disputes to which they otherwise would not have needed to pay attention.”
The islands say Britain breached its obligation to negotiate a nuclear disarmament under the 1970 Nuclear Non-Proliferation Treaty — and argue India and Pakistan have breached similar obligations under customary international law.
The archipelago originally filed suit against nine states, including declared nuclear powers China, France, Russia and the United States as well as Israel and North Korea.
However, only the three countries that have made a commitment to respond to suits brought at the ICJ will be in court.
In another David-and-Goliath case, the Pacific island state of Palau, that is threatened by rising sea levels, is pushing for the United Nations General Assembly to ask the ICJ for an advisory opinion on the obligation of the world's nations to combat climate change.
The government of the Indian Ocean state of the Comoros Islands asked the International Criminal Court to investigate a 2010 Israeli raid on a Comoros-flagged ship carrying activists seeking to land in the occupied Palestinian Territories to deliver humanitarian aid.