POSSIBLY the worst response to the crimes of the Islamic State (Isis) death cult is, as David Cameron did, to claim that it poses an “existential threat” to our way of life.

To imagine that modern states where people have fought for generations to build democracy and an increasingly secular society will bow the knee to this barbaric development shows little confidence in “our system of values.”

Cameron’s professed recourse to a “full spectrum response” explains partly why some people have fallen for this obscurantist brutal sect.

He portrays Western nations as hapless victims of Isis as though Nato and its member states have played no role in the terror group’s development.

The text of his “basic rules in terms of our engagement” with imams, Muslim communities and organisations betrays an imperialist mindset by citing a view that “it’s all right to be a suicide bomber in Israel.”

The key question is not about how bombs are delivered — by an individual wearing a bomb belt or by high-altitude state-of-the-art warplanes provided by the US military-industrial complex.

Cameron’s “basic rules” effectively demand complicity by Britain’s Muslim communities in Israel’s blood-soaked occupation of Palestinian land.

Killing over 2,000 Palestinians, including 500 children, in a gory onslaught against Gaza is no less terrorist than an individual suicide bomber detonating explosives in a bus, train or restaurant.

Where Cameron departs from most people in Britain — not just Muslims — is that he justifies Israel’s crimes because he sees Tel Aviv as a reliable ally in an unstable region.

And why is it unstable? Could it be the legacy of British and French colonialism, the installation of pliable autocrats in local remnants of the Ottoman empire and ongoing Nato military backing of these dictators?

Could the instability be related to the plethora of US-led imperialist wars that destroyed state power in Iraq and Libya, leaving the way clear for Isis-linked groups?

Supporters of this succession of illegal invasions and of Israel’s colonisation of Palestinian land would have us believe that there is no link.

But this flies in the face of both logic and the justifications offered by people attracted to religion-influenced extremism.

Cameron’s invocation of democracy will ring hollow in most Arab states, where secular democratic opposition movements, often linked to the left, existed but were oppressed with Western approval or silence.

Abstract calls for democracy will fall on deaf ears until it can be shown to deliver.

Electorates throughout much of the Middle East and Africa may vote for economic progress, but Western domination of global trade and finance depresses living standards for most people.

Frustration at this situation can express itself in efforts to migrate to economically advanced countries or support for Isis.

Cameron attacks others for their supposed “put your head in the sand” stance, but he is guilty of this, believing that the world can remain unchanged, with the same global injustices, and that Isis can be defeated by a combination of aerial bombing, military backing for Western-approved governments and greater reliance on security services.

He’s living in a fool’s paradise. Those made desperate and susceptible to jihadist ideology cannot be defeated militarily.

Cameron claims to champion an “integrated, democratic, successful, multiracial Britain.”

But such a positive aim must be mirrored in a foreign policy based on solidarity, joint endeavour and mutual respect rather than capitalism’s beggar-thy-neighbour approach that prizes oil reserves and other resources over equality, civil rights, democratic accountability and human development.