It’s easy to rewrite history once you control the narrative. Everything is yours to tweak and refine. The history of international politics seems not to exist before 2003, and everything that was and is comes after the Iraq War.

The narratives on this are dictated by those on the left. We were right to warn against invasion and there was a myriad of reasons, not least that there was no post-conflict strategy for reconstructing the country. Crucially, there was little local support for the overthrow of a brutal fascist regime. The Iraq War was a mistake and it has not made the world a safer place.

But we see to have reached a stage where any discussion around military intervention becomes curtailed by flashbacks to the 2003 invasion. Intervention is now seen as innately imperialistic, based around violent self-gain on the part of the western forces. It’s a line echoed strongly by those from Stop the War Coalition and parts of the Labour Party. And it also floats the idea that foreign policy directly leads to terrorism, something Jeremy Corbyn echoed this week in the aftermath of the terrorist attack in Manchester.

Here is the problem with the discussion regarding terrorism and the factors that drive it. Those who are ideologically opposed to foreign interventions and those who see an inherent problem within Islam have a tendency to shift the blame solely on one factor and overstate its importance. Meanwhile the rest of us in the middle sit exploring the factors that link everything together, crying out for a mature discussion.

Western foreign policy has often been misguided, from effectively training future terrorist groups to destabilising certain countries. Denying that is pointless, and there is certainly a link between that and the grievance it creates. Security analysts have on numerous occasions linked Iraq War to an increase in security threats for many countries. It is a factor and at times a very strong factor in what radicalises some individuals.

And yet there is a massive gap between anger at foreign wars and deciding to massacre children. Within that gap exists alienation, a search for identity that comes from the feeling of being estranged from wider society, due to both racism and failed cultural integration, and also exists a murderous barbaric ideology.

Islamism does not need foreign policy to exist. It is powerful enough on its own, and ISIS have made it clear that with or without foreign policy, they would loathe the west. 9/11 preceded both wars in Afghanistan and Iraq. Islamism as an ideology predates western involvement within the Islamic world, and fundamentally rests on the old premise that it’s a duty to establish an Islamic society, that non-Muslims are inferior.

Those who believe this, and violently enact it, would not suddenly twitch with guilt and hesitate had foreign policy not existed. They subscribe to an ideology that brings them to regard the west as the complete antithesis to everything they stand for. We are remarkably apologetic for Islamism, when other totalitarian creeds such as communism or fascism received no such sympathy.

Maybe some, such as Andy Burnham, are worried to say ‘Islamism’ because it might paint Muslims as terrorists. Islamism is not Islam. But it’s a strand of this religion, and one that at various points of history has been prominent and powerful. Some Islamic dynasties focused heavily on arts and science, but there have been many points when Islamism has been dominant. Have Saudi Arabia and their Wahhabism contributed? Undoubtedly, and yet these Islamist groups abhor Saudi Arabia. And though their ideological principles overlap, it does not mean their beliefs came from Saudi Arabia.

And that is not to say either that simply ideology radicalises people. Identity, and the search for it, contributes massively. Many of those committing the acts are not religiously literate yet still strongly claim to being a Muslim in their actions. The Muslim identity has transcended theology and become a political and cultural identity, one that that finds a sense of belonging sometimes in the Islamist movements. The point here is to show that many different factors create conditions for radicalisation and ideology and alienation are two powerfully entwined ones.

Moreover, to say that foreign policy creates these terrorists overlooks some basic points: these people have attacked countries that were not involved in the Iraq War such as France or those with peaceful foreign policies like Sweden. They attack other Muslims, such as Shia Muslims, and have regularly attacked Muslim countries. Why? They see the march of liberal secularism in the age of globalisation as a threat. They regard the slightest deviation in faith as heresy, and punishable by death. They see Shia Muslims as abominations, and would have massacred the Yazidi people had NATO not intervened.

To which some other things must be noted. Many people joined ISIS to fight Assad because the west was inactive against the Syrian dictator. During the 90’s, Islamist groups like al-Muhajiroun were enraged that the west failed to take military action over the Bosnian massacre that took place in Srebrenica. Salman Abedi’s parents were refugees who fled the Gaddafi regime yet are we to believe he was enraged that the west stopped the same dictator from carrying out a massacre against the people? Consider that the growth of ISIS within Syria right now gravitates around the idea that they are the only shield against Assad’s war machine.

Radicalisation is a complex web of many factors of which foreign policy is one strand and that is the point. We either overplay its importance or completely eliminate its significance. There is almost definitely a point to be made in how the west conducted itself in Libya, departing too soon after removing Gaddafi. But the alternative to intervention was witnessing Libya descending into the same death toll as Syria. And in this world that we live in, international isolationism is not an option. We have a moral duty, and as decreed by international law, a responsibility to protect, to act when states have decisively failed in protecting their people.

When we discuss radicalisation we often lack nuance. Everything is either foreign policy or Islamism. We overlook that these factors all play a part in tandem rather than separately. Someone can be angry about a foreign war but is that enough to prompt them into attacking children? There has to be something that justifies that to them, that is the ideology. There has to be something that draws them to the ideology, and that’s the search for an identity and sense of belonging.

Rabbil Sikdar

Liberal Muslim, socialist, contributor to Huffington Post, Independent and New Statesman. Graduate in Politics and IR.