Nadhim Zahawi is a member of the Foreign Affairs Select Committee and MP for Stratford On Avon.

Last week I travelled to Iraq and Turkey as part of the Foreign Affairs Committee delegation investigating how to defeat ISIL and end the Syrian Civil War. This was the first time I’d visited since ISIL terrorists downed the Russian plane in Egypt, struck in Paris and bombed Beirut, and you could sense the change. These tragic events have sped up what was previously slow progress in the diplomatic situation. An atmosphere of determination to end this reign of terror once and for all has emerged.

This determination coalesces around the new talks John Kerry is leading in Vienna. From them, the International Syria Support Group (ISSG) has emerged. Iran is involved in these talks for the first time, and the distance between Russia and the West is narrowing. There is common ground from which a political settlement could be found.

Soon, the House of Commons will vote on extending British airstrikes into Syria. Legal bases were already covered by the United Nations enshrined right to self-defence for Iraq and the Western nations involved. Now, however, Security Council Resolution 2249 has added duty to right. It calls “upon Member States that have the capacity to do so to take all necessary measures, in compliance with international law…to redouble and coordinate their efforts to prevent and suppress terrorist acts committed specifically by ISIL…and to eradicate the safe haven they have established over significant parts of Iraq and Syria”. Britain, a great power, cannot stand back from its responsibility.

Military intervention won’t work without a political settlement and David Cameron knows that. That’s why the motion to extend British military intervention against ISIL into Syria has been positioned within the comprehensive international strategy for combating them. It is to this strategy that Britain will add unique war-fighting capabilities that even the United States lacks.

On top of the additional military strikes we should carry out, we’re already putting our full diplomatic weight at the ISSG behind securing a transition to an inclusive government in Syria. We’re also helping to support and maintain the moderate rebels of the Free Syrian Army in their fight against Assad and ISIL. As the Prime Minister has said, these groups are integral to Syria’s future and we will work around the clock to convince Russia of that fact. They have had more success against ISIL than anyone else in Syria and have demonstrated that they can successfully administer territory they capture. When Russia strikes them, they help ISIL and this needs to end. Russia doesn’t want ISIL to continue existing any more than we do and although Putin is evidently caught between aiding Assad and defeating ISIL, he has surely realised that it’s time for a new approach. This is an area where I believe our diplomacy will win out.

Now that states are signalling that they wish to bury the differences that deepen the conflict and play into ISIL’s hands, real military progress against them in the core of their self-proclaimed Caliphate is a possibility. At the heart of this military solution are Sunni fighters and security forces. This applies both in Syria and Iraq.

Nothing can be achieved without this. ISIL would like nothing better than for Western air forces, Iranian soldiers and Shia militias to be the only forces leading the fight against them. That would feed into all their propaganda and the narrative on which their wicked project is built. The brutality of Assad in Syria and some Shia militias in Iraq, as well as the policies of the Maliki government, pushed ordinary Sunnis towards ISIL out of fear. This allowed them to hold territory far too comfortably. Only a political settlement can bring about the strong Sunni opposition and military power that will topple them.

In Syria that means uniting the opposition militias and the Free Syrian Army, excluding extremists such as the al-Nusra Front, and shifting the front south and east. In Iraq that means creating better police forces in Sunni Arab majority Anbar and Nineveh provinces – as the Italian Carabinieri are excellently helping to do – and encouraging authorities in Baghdad to create a National Guard to replace Shia militias. In Iraq last week, it was made clear to us that this creation of an anti-ISIL Sunni force would destabilise their hold on Anbar and make it harder for them to hold Mosul against the coming Iraqi offensive.

This is still possible. For all Assad has done in Syria and after all that Maliki’s government did in Iraq to marginalise and abuse Sunnis, ISIL are still not seen as a vehicle for Sunni hopes for the future. We must provide one. If we can, ISIL’s real weakness will be revealed. We know from our allies in the region and intelligence that they are clearly seen as an occupying force of foreign fighters spreading fear and terror. Their claim to religious purity is rendered transparent by the cruelty, bloodlust and sexual slavery they bring to those they conquer. Once isolated they will not be able to hold on. Without territory, their ability to plan attacks on us at home will fall dramatically too.

For all these reasons it is clear that it makes no military sense for us to limit our efforts to Iraq alone. ISIL see no border and we shouldn’t aid them by giving them safe haven and a logistical space to regroup. I will join the Prime Minister in voting for the strikes and I hope that colleagues on both sides of the House will join me in doing so.