What have the son of a Liberian dictator, a rabidly anti-Jewish Australian and a Rwandan diplomat all got in common? They are all defendants where courts in one state are seeking, or have recently sought, to decide criminal liability for alleged actions in another. As such, they illustrate the best and worst of, and the difficulties involved in, the development of transnational jurisdiction.

The dictator’s son is Charles ‘Chuckie’ Taylor. The father is currently defending a war crimes rap at the International Criminal Court; the son was sentenced to 97 years by a Florida court earlier this month for alleged torture in Liberia. He is the first person successfully prosecuted in the US under its Extraterritorial Torture Statute 1994. This legislation gives jurisdiction to the US courts over torture wherever it is committed. Taylor is the US equivalent of Farayadi Sawar Zardad, the first person to be convicted in 2005 on the basis of a similar jurisdiction of the UK courts.

The Australian is Dr Frederick Töben, a German-born naturalised Australian citizen. He runs the Adelaide Institute, whose website proclaims: ‘The Holocaust-Shoah is pure hatred against Germans and anything to do with Germans’. Dr Töben took a risk last October. He knew that Germany had issued an arrest warrant against him for alleged holocaust denial but thought he was safe breaking a flight at Heathrow because the UK is not part of the Schengen travel area and holocaust denial is not currently an offence in the UK (though this may change under EU legislation yet to come into force).

Alas for Dr Töben, the European arrest warrant applies between all the countries of the EU. It requires pretty much automatic recognition of a warrant made in relation to a specified list of crimes, whether or not the alleged conduct complained against is an offence in both countries. For categories such as murder, this is unproblematic. However, one or two are both indistinct and controversial: most notably ‘racism and xenophobia’. This was inserted even though everyone predicted a potential clash between countries such as Germany and Austria, which criminalise holocaust denial, and those that do not. In the event, Dr Töben was rather lucky: the warrant was initially ruled invalid for insufficient particulars of the alleged crime. Bail was granted pending appeal, but the Germans gave up – though Dr Töben had spent three weeks remanded in custody before they did.

Rose Kabuye is the Rwandan diplomat. She has been targeted by the French judge Jean-Louis Bruguière. Nicknamed the ‘cowboy’ for his gunslinging approach to the law, Judge Bruguière has charged Ms Kabuye with blowing up the plane of Rwanda’s then president and, thereby, offering Hutu militias a pretext for the massacre of Tutsis. The judge claims French jurisdiction on the basis of the nationality of the two pilots who were killed in the crash.

Ms Kabuye’s trial in France would certainly force the issue of possible French involvement in the Rwandan massacres. Back home, she is a widely popular former resistance leader who has played a prominent part in the rehabilitation of her country.

Were she to be found guilty of the alleged murder that preceded the death of up to a million Tutsis, her conviction would help exculpate the French government from the allegation that it was implicated in setting up the alleged initial assassination. Puzzling elements of Ms Kabuye’s behaviour – such as her decision to travel to Germany on a private passport while on a diplomatic mission – have suggested that she is up for the fight. The German courts are clearly a little confused and allowed Ms Kabuye home for Christmas: they may have hoped she would not return. Der Spiegel has carried articles pointing out that this prosecution is convenient for French government foreign policy.

We live inescapably in a globalised world, which demands a response from judges just as much as legislators and governments. As Lord Bingham argued in a recent lecture, ‘If the daunting challenges facing the world are to be overcome, it must be through the medium of rules, internationally agreed, internationally implemented and, if necessary, internationally enforced. That is what the rule of law requires in the international order.’

Prosecutions like that of Taylor and Zardad show the principle working at its best. The cases of Dr Töben and Ms Kabuye raise more difficulties. Germany attempted to prosecute Töben in Europe for material uploaded to the internet from Australia, even if publication might be argued to occur wherever the website was read. The European arrest warrant meant that a UK court had to decide whether it would be complicit in that prosecution. The abolition of dual criminality for vague categories of offences is unfortunate. Ministers need to deal with the difficult compatibility issues at the time of drafting and not just leave them for judges to subsequently sort out. The most sinister interpretation of Ms Kabuye’s prosecution could indicate how national interests might on occasion abuse the European arrest warrant system, which is not to say that they actually have done so in her case.

The whole idea of mutual recognition will break down if not exercised with sensitivity – and particularly if over-influenced by political considerations.

The inexorable logic in the longer term is surely that the world would benefit from the extension of the jurisdiction of the International Criminal Court. This would be the body best suited to decide on the guilt or otherwise of Liberia’s feared anti-terrorist unit, the author of anti-Semitic Australian websites (if the world wants to agree that this is a crime) and alleged conspirators to killings in Rwanda. Practically, though, that day is a long way off. In the meantime, we muddle forward.

Roger Smith is director of the law reform and human rights organisation Justice