Lawfare was first defined in 2001 as ‘the use of law as a weapon of war’. Last week, it was the focus of an important conference in New York organised by the newly-established Lawfare Project.

The metaphor of war is never far from the courtroom. We talk routinely of ‘preliminary skirmishes’, of ‘fighting legal battles’, of ‘defeating’ the other side. But lawfare is no metaphor. It involves exploitation of the law to undermine a democratic state.

The laws being exploited may be those of the state which is being targeted. For example, researchers who expose the funders of international terrorism have found themselves sued for defamation or hate-speech. However, lawfare is also an international phenomenon.

Charles Dunlap, the military lawyer who coined the phrase, later expanded the definition to cover ‘the strategy of using – or misusing – law as a substitute for traditional military means to achieve an operational objective’.

And Gabriela Shalev, Israel’s ambassador to the United Nations, told the conference – held at the New York County Lawyers Association, just across the road from the gaping hole where the World Trade Center once stood – that ‘certain democratic states’ had extended laws of war beyond their territorial limits.

‘These laws are grossly misused in an asymmetric manner by terrorists’ supporters as a political tool of lawfare,’ she said.

The ambassador mentioned no states by name. But she was speaking only a week after Jack Straw had told parliament that Britain was ‘minded’ to change laws under which arrest warrants have been granted for former Israeli generals visiting London.

As the justice secretary explained, the Geneva Conventions Act 1957 allows anyone currently in the UK to be prosecuted for a war crime committed anywhere in the world.

Such ‘universal jurisdiction’ can be a force for good: it led to the imprisonment in 2005 of Faryadi Zardad, an Afghan warlord tracked down by the BBC to Streatham, south London. And war crimes legislation contains safeguards against abuse: no prosecution can go ahead without the permission of the attorney general.

However, no such consent is required for an arrest in England and Wales. Anybody may go to a magistrate and apply for a warrant. As Straw explained, all you need is ‘some prima facie information that an offence known to the law has been committed by the person named’.

That is what the government is proposing to change. Ministers have concluded ‘that there is a case for restricting to the Crown Prosecution Service the right to prosecute this narrow range of universal jurisdiction offences, in circumstances where the offence is alleged to have been committed outside the United Kingdom by a person who is not a British national’ nor subject to service law.

A private individual could still apply for a summons or warrant if an offence of universal jurisdiction had been committed in the UK, or if the suspect was a British national or a member of Britain’s armed forces.

But only the CPS could obtain arrest warrants against foreigners suspected of committing war crimes abroad. And prosecutors would act only if they expected to obtain sufficient evidence and thought that a prosecution would be in the public interest.

Although the necessary amendment to the Prosecution of Offences Act has been drafted and circulated, there is, of course, no prospect that it will become law before parliament is dissolved. Just to make sure, the justice secretary announced a one-month consultation period, to expire on the day the general election is expected to be called.

Even though there is no commitment to legislation, Straw’s announcement will be seen as a setback for those who seek to use lawfare against Israel. On a visit to the West Bank in January, the attorney general was told by human rights groups that universal jurisdiction was the Palestinians’ only hope of justice. They told Lady Scotland that their attempts to have visiting Israelis arrested in London were serious legal moves rather than publicity stunts.

Daniel Machover is the London solicitor who obtained a warrant for the arrest of a retired Israeli general at Heathrow Airport in 2005, only to find the arrest thwarted when someone – it’s thought Scotland Yard – tipped off the Israeli embassy. The general denied any wrongdoing.

At a debate in London last month organised by Lawyers for Palestinian Human Rights, Machover argued that the point at which an arrest was being considered was too early to decide whether a prosecution would be in the public interest. That assessment was normally made at the charging stage, after the evidence had been obtained.

He did accept, however, that if there was to be a change in the law then the power of consent to an arrest should be in the hands of the CPS rather than the attorney general.

Machover was responding to a speech by Lord Pannick QC, who said it was anomalous that a person might be arrested with no consideration of whether a prosecution would be in the public interest. Pannick told the Palestinian human rights supporters that the attorney general was better placed than the CPS to decide whether an arrest should be made – because the attorney could assess the international implications and was answerable to parliament.

These days, people seem very unwilling to accept that the attorney general can take such decisions in the wider public interest and on a non-political basis. Perhaps that’s why Jack Straw is proposing to give this role to the CPS. But he is right to propose reforms. There is nothing to be gained by an arrest of someone who is never going to be prosecuted.