Crime doesn’t pay, at least not electorally. Crime has fallen steadily in the United Kingdom and across the Western world since 1994 – coincidentally, the year after a young Tony Blair, then still shadow home secretary, called for the country to be “tough on crime, and tough on the causes of crime”.

Those ten words occupied a fraught place in the inner life of the New Labour government: it was Gordon Brown who originally coined them, but Blair who brought them into the national consciousness and reaped the political rewards afterwards. “Law and order” was comfortable territory for New Labour, whose senior figures felt they had a good story to tell and the right policy analysis, too. (There were 53 criminal justice bills under New Labour, and eye-catching initiatives included the creation of “Asbos” and police community support officers, as well as the widespread use of CCTV cameras.)

Labour is a very different party nowadays, but Jeremy Corbyn also feels this is fertile territory for him. He has attacked Theresa May over cuts to youth services and police numbers, bringing in both her record as home secretary and the austerity policies of David Cameron’s government. The 2017 Labour manifesto even contained these 12 words: “Labour is tough on crime, and tough on the causes of crime” – which went largely unnoticed and unremarked.

However, what that manifesto offered is only half the story. What it left out is also telling: anything resembling a radical criminal justice policy. Labour had strong criticisms of Tory cuts to the prison estate, but could not bring itself to say that the answer to overcrowding might be fewer, shorter jail sentences, and not just more funds.

The manifesto also did not mention a major area where a policy change could reduce unnecessary incarceration and lead to money being taken out of the hands of gang leaders and put into the Treasury – that is, the liberalisation of drug laws.

The word “drugs” features just twice: once in reference to the NHS, and once in reference to the need for a better-funded border force to prevent smuggling.

In most policy areas, there is a greater divide between Corbyn and May than there is between any of their predecessors in the same roles. Yet on law and order, Labour’s solitary objection is that the government isn’t spending enough money on grappling either with crime or the causes of crime, such as shuttered youth centres and cuts to police budgets.

Why does this policy area feel so underexplored by Corbyn’s self-professed band of radicals? Partly because, until the recent spree of fatal stabbings in London, crime had slipped down the political agenda.

During the elections of 1997, 2001 and 2005, it was ranked by the voters as one of the top three issues facing the country. But the prolonged drop in the volume of crime meant that it had all but vanished as a political divide by 2010, and was wholly absent in 2015 as well.

That gave the Labour leadership licence to rebrand the party as an advocate for the status quo on crime and policing. This orthodox approach is favoured by Richard Burgon, the eager Corbynite who shadows the justice department.

However, it is tempered by the discreet radicalism of Diane Abbott. She has moved the party quietly to a bolder position on refugee rights and, in February, she became the first shadow home secretary to visit the Yarl’s Wood detention centre, which houses women prior to their deportation from the UK.

Yet now crime, and especially violent crime, is back – and people are worried. Because of May’s history at the Home Office, the issue will be a running sore for the Conservative Party for as long as she is in Downing Street. The Prime Minister made her name by facing down the Police Federation’s calls for more cash and by curbing the illegal use of stop-and-search without compromising the number of resulting arrests. That means she cannot easily revive the perennial Tory explanations for the rise in crime – not enough bobbies on the beat and too much red tape.

When May is replaced as prime minister – still a more likely outcome than her contesting the next election – her successor will no doubt resurrect the old Conservative shibboleths: that stop-and-search, whether illegal or not, is a legitimate part of the police playbook and that the problem for officers is not spending cuts but excessive regulation.

However, the facts are on May’s side: Home Office research suggests that the changes in stop-and-search have not contributed to the rise in crime, as has been claimed. (Unfortunately, the cuts to police budgets have.)

But facts don’t always matter in politics as much as they should, and the next Tory leader will find it easy to reach for the usual explanations if put under pressure. Polling consistently shows that two-thirds of the public support reducing policing restrictions and “red tape”.

So, Corbyn faces a tough choice. Labour’s 2017 platform leaves him in the worst of all worlds: out of step with the public’s draconian instincts, yet not particularly radical in his proposals, either.

He could match the Tory offer with fewer limits on police and tougher sentences for offenders, but no one in the leader’s office thinks Corbyn would be able, or willing, to pull this off. He could continue to talk about criminal justice only as an example of the wider consequences of the Conservative economic model.

Or he could be daring, if unpopular: argue for prison and drugs reform. That is to say, Labour could acknowledge that the causes of crime cannot be tackled merely by putting more money into the state, but by changing what the state does.