In UK and Ireland, protesters who have deliberately damaged military equipment are walking from the dock.

Two days before the attack on Iraq, two men in their 30s, Phil Pritchard and Toby Olditch, cut through the fence surrounding the US air base at Fairford in Gloucestershire and made their way towards the B52 bombers which were stationed there. The planes belonged to the US air force. The trespassers were caught by guards and found to be carrying tools and paint. They confessed that they were seeking to disable the planes to prevent war crimes. This year they were tried on charges of conspiracy to commit criminal damage, which carries a maximum sentence of 10 years. Last week, the jury failed to reach a verdict.

The same thing happened a month ago. Two other activists, Margaret Jones and Paul Milling, had entered the same air base and smashed up more than 20 of the vehicles used to load bombs on to the B52s. The charges were the same, and again the jury failed to agree. In both cases the defendants claimed to be putting the state on trial. The defendants had tried to argue that the war against Iraq was a crime of aggression. But this March the law lords ruled that they could not use this defence: while aggression by the state is a crime under international law, it is not a crime under domestic law. In summing up, the judge told the jurors that using weapons “with an adverse effect on civilian populations which is disproportionate to the need to achieve the military objective” is a war crime.

While these non-verdicts are as far as the defence of lawful excuse for impeding the Iraq war has progressed in the UK, in Ireland and Germany the courts have made decisions whose implications are momentous. Last year, five peace campaigners were acquitted after using an axe and hammers to cause $2.5m worth of damage to a plane belonging to the US navy. When they attacked it, in February 2003, it had been refuelling at Shannon airport on its way to Kuwait, where it would deliver supplies to be used in the impending war. The jury decided that the five saboteurs were acting lawfully. This summer, the German federal administrative court threw out the charge of insubordination against a major in the German army. He had refused to obey an order which, he believed, would implicate him in the invasion of Iraq. The judges determined that the UN charter permits a state to go to war in only two circumstances:

in self-defence, and when it has been authorised to do so by the UN Security Council. The states attacking Iraq, they ruled, had no such licence. Resolution 1441, which was used by the British and US governments to justify the invasion, contained no authorisation.

There is no prospect that the British PM could be put on trial for war crimes in the UK (although international lawyer Philippe Sands says there is a chance he could be arrested and tried elsewhere). Even so, the British government appears to find these legal processes profoundly threatening. When the Fairford protesters took their request to challenge the legality of the war to the court of appeal, Sir Michael Jay, permanent under-secretary at the British Foreign Office, submitted a witness statement which seems to contain a note of official panic.

“It would be prejudicial to the national interest and to the conduct of the government’s foreign policy if the English courts were to express opinions on questions of international law concerning the use of force which might differ from those expressed by the government,” he wrote. Such an opinion “would inevitably weaken the government’s hand in its negotiations with other states.” It doesn’t seem to matter how many journalists, protesters or even lawyers point out that the British government had no legal case for attacking Iraq, that the attorney general’s official justification was risible and that Blair’s arguments were mendacious.

The prosecutors have lost before. In 1999, a sheriff at the court in Greenock, Scotland, instructed the jury to acquit three women who had boarded a Trident submarine testing station on nearby Loch Goil and thrown its computers into the sea. In 1996, four women were acquitted of conspiracy and criminal damage after disabling a Hawk jet which was due to be sold by BAE to the Suharto dictatorship in Indonesia. Their acquittal might have helped persuade the late Robin Cook then UK foreign secretary to seek to introduce an “ethical dimension” to foreign policy in 1997.

It is true that such verdicts impose no legal obligations on the government. They do not demonstrate that its ministers are guilty of war crimes. But every time the prosecution fails to secure a conviction, the state’s authority to take decisions which contravene international law is weakened. These cases cannot reverse the hideous consequences of the crime of aggression that Blair and Bush committed in Iraq. But they do make it harder to repeat. — The Guardian