Gary Slapper: The war in Iraq shows international law will always struggle to control individual national militarism

What future is there for international law after the war in Iraq? Through the eyes of many, the law failed both to control the savage and tyrannical regime in Iraq for the last decade, and then failed to control the way the regime was ousted.

The truth is that while law is becoming more global in its application to many things, from pollution to internet libel, it still struggles to harness the horse of national militarism.

In many ways, law is the most powerful force on earth. It controls what most people do most of the time. It can drag a serving American President – Bill Clinton – into its processes, and pull into its courts former state leaders such as Senator Augusto Pinochet, the former President of Chile, and Slobodan Milosevic, the erstwhile President of Yugoslavia. Preventing or controlling war, on the other hand, is another matter.

Since it was first named in 1780 by the jurist Jeremy Bentham, "international law" has faced many challenges. John Austin later denied it was real law as it neither emanates from one sovereign source, nor is it enforced in the same way as ordinary domestic law.

If countries take a legal stance that indirectly affronts their fellow nations, there is little that can be done using remedies of law. Saddam Hussein could not be removed simply for being a tyrant, nor can North Korea be sued for apparently reneging on its promise not to develop a nuclear military capacity.

After fighting in Afghanistan, the US developed the novel legal category of "unlawful combatant" for those it wanted to interrogate in Guantanamo Bay. Such suspects were neither entitled to "due process" as defendants, nor were they entitled to be treated within the terms of the Geneva Conventions. There was nothing any other countries could do about this.

America's consideration of the doctrine of "odious debt" for a post-Saddam regime in Iraq is also the source of international disquiet. The doctrine, developed by the US in 1898 in relation to Cuba's debt to Spain, says a new incoming regime does not have to honour debts incurred to other nations by a previous despotic regime if the borrowings were not in the interests of the population. In Iraq, that would jeopardise the repayment of over $50bn to France and Russia.

The Charter of the United Nations (UN) came into force on 24 October, 1945, aiming "to save succeeding generations from the scourge of war, which twice in our lifetime has brought untold sorrow to mankind". There has not been a single day of world peace since that statement was published so, in one view, the UN has been ineffective.

However, active democracy is the best antidote to violent minorities. The more we become a global village, the more possible it is for rules to be applied by a world community to all equally. Rules always work best in a democracy.

Gary Slapper is Professor of Law, and director of the Law programme at the Open University