Jack Merritt and Saskia Jones were killed at London Bridge on Friday, at a conference on prisoner rehabilitation. Their murderer, Usman Khan, had been imprisoned for terrorist offences, and was released last year; the Guardian warned at the time that the police and probation services lacked the resources to deal adequately with a wave of prisoner releases. Khan was electronically tagged, and had been given permission to go to the conference. It seems he planned the attack, making himself a fake suicide vest. He was stopped from further bloodshed when members of the public, including other former prisoners at the conference, intervened to stop him. Police, responding to the hoax vest, shot and killed him. Merritt’s grieving father made this plea: ‘My son, Jack, who was killed in this attack, would not wish his death to be used as the pretext for more draconian sentences or for detaining people unnecessarily.’

That wish has already been trampled. The major parties paused their campaigning on Saturday, but Boris Johnson wasted no time in exploiting the attacks: in a flagship article in the Mail on Sunday, and in an interview with Andrew Marr on BBC One, the prime minister peddled a plan – conjured out of thin air with expeditious cynicism – for harsher and more draconian sentences; he blamed Labour for Conservative policies; he slid into conspiracy theory while rambling that Corbyn wanted to abolish MI5. The justice secretary, Robert Buckland, added this morning that his department would be looking at ‘a few hundred’ people who may not have committed offences but hold ‘extreme’ views – suggesting that they might also be detained, in contravention of the Human Rights Act.

The spiral into law-and-order posturing is the only option left for a Conservative government that has presided over a prison system rife with violence and abuse. The chief inspector of prisons said last year that the appalling conditions had ‘no place in an advanced nation’. Recruitment to terrorism in jail can fester unchecked. The prisons budget has been cut by nearly 40 per cent under successive Tory administrations. Its ‘deradicalisation’ programmes are risible, unserious efforts by a government unwilling to face the problem and baulking at the hard, one-to-one work needed for real success: the desultory efforts now in place are often inaccessible, even to the few – including Khan, according to his former lawyer – who ask for them.

The disastrous part-privatisation of the probation service, the burnout and overwork of the officers left in its public remnant, who have to deal with the most dangerous cases, should also now come under the spotlight. Reports warning of the risks were watered down and made to disappear during Liz Truss’s tenure at the Ministry of Justice.

Throughout the election campaign, Johnson has insisted that his is a new government: but he was in cabinet, and an enthusiastic pillar of the Tory Party throughout this long indolence in office; his new government, too, is filled with those who oversaw, approved and shrugged off responsibility for the systemic neglect. They are the authors of the past decade.

Nazir Afzal, a former chief prosecutor for the North-West of England, has described a conversation he had with Johnson in 2016, when he was still foreign secretary. Johnson asked Afzal what kept him awake at night. The gaps in deradicalisation programmes, he replied, and the government’s unwillingness to fund more serious versions. Johnson shrugged it off: ‘there was no money.’ The Tories are happy to profit from the cheap rhetoric of imprisonment and punishment, but unwilling to meet the real cost of the measures that those close to the system know it needs.

There are two ways of thinking about terrorism. The first treats it as an incomprehensible – ‘senseless’ – eruption of violence into ordinary life, in which no internal logic, however warped, is discernible; any attempt to understand it is tantamount to treason. On this view, the only solutions are ever more intense surveillance and ever harsher prison sentences. The second view insists that terrorists are made, not born; that to explain is not to endorse; that thinking of terrorist ideology as a lethal political pathogen misses the conditions that have allowed it to set down roots. On this model, a struggle against political violence requires not only a patient, ruthless disarticulation of terrorist thinking, but an unflinching examination of the grim conditions it purports to explain.

Almost all thinking on terrorism shuttles between these two models, though the former predominates in times of crisis; the latter requires a kind of accounting usually unpopular with politicians, but more widely understood among the public. After the Manchester bombings in 2017, Corbyn breached the taboo by linking Britain’s conduct abroad to its security at home; an instant poll by YouGov found that over half the public agreed with him. Commander Neil Basu, the Met’s most senior counter-terror officer, argued a few months ago that the remedy to terrorism cannot ultimately lie in policing – which deals in effects, not causes – but that ‘more social inclusion, more social mobility and more education are much more likely to drive down violence’.

Johnson has been criticised in sections of the press for politicising a tragedy. But Merritt’s father’s intervention was not an abstract plea to put the event beyond politics; it was a warning against the cynical ends to which he feared it would be put. More, not less, politics is needed in response. The last three major political exercises in this country – the general elections of this year and 2017, and the referendum of 2016 – have been stained with acts of violence and terror. They are attempts to degrade and violate the democratic process at times of intense political volatility, and to force it into a spiral of confrontation and repression, enlisted by demagogues promising easy solutions: longer sentences, harder borders, fewer liberties in the name of security.

Jack Merritt’s work was dedicated to the possibility that education could form a basis for drawing the poison of terrorism; a foundation for rebuilding the wreckage in our prisons, which our leaders discard and forget. His father, seeing today’s front pages, intervened again: ‘Jack stood against everything you stand for – hatred, division, ignorance.’ Perhaps it is time some politicians listened.