David Cameron made a characteristically fluent case on Thursday. But he did not actually answer the two critical questions that must precede any decision by Britain to initiate hostilities within Syria: namely, what is the political end game and what is the military plan to achieve it?

The first is incredibly difficult but not impossible. We need to drag all the interested parties around a table and hammer out a mutually acceptable solution.

If we are still a long way from a consensus, it is because most of the main players seem more intent on destabilising their enemies than stabilising their friends.

Saudi Arabia and the Gulf states have a history of enabling financial support for any jihadi group that attacked the Shia – including Isis. Turkey has facilitated the sale of up to a billion dollars of Isis oil, has held open the border for jihadi groups and their intelligence agency has supplied arms to jihadis in Syria.

We need to bang our supposed allies’ heads together and stop this nonsense. It can be done. The Arab nations are waking up to the dangers of their own activities, with the sacking of some of their pro-Isis ministers. Similarly, the Russians need to grip the Iranians.

And we have to stop obsessing about Assad. His regime is vicious, but so is nearly every active player in this conflict. The British government’s line smacks of a retrospective wish to justify its abortive 2013 attempt to bomb him. But the Syrian government still controls most of the cities and is the only plausible guarantor of the safety of all the non-Sunni communities threatened by a jihadi victory. The wisest course is to start negotiations on the future of Syria and Iraq without any preconditions.

The second unanswered question is even harder. What is the military plan? Since we cannot win with air alone, this reduces to “where will we find a pro-western army?”

David Cameron asserted that the “Free Syrian Army” commanded 70,000 troops. What this probably refers to is a disparate range of up to 1,500 different tribes and villages, in possibly 40 loose associations. Many of these operate under the control of Isis or the two essentially al-Qaida affiliates. Only the Kurds are in truth independent of the jihadis.

So this 70,000 is probably a phantom army. Which means that the military force will have to be a regional one, which in turn depends on the Vienna process reaching some form of mutually acceptable conclusion between all the regional powers. In this, Britain could have a very real role, which we should not miss in the heat of the moment. And it is at a time when the Russians are signalling in numerous ways that they are willing to play a real constructive role.

And that is part of the risk of the obsession with British bombing.

Despite the brave words of the prime minister, we will add very little to the military impact. Besides, military actions by themselves are not enough. The best lesson here is the spectacularly successful military action that we and the Americans carried out when we completely wiped out al-Qaida in Iraq. We simply created the vacuum that was then filled by Isis, because we did not fix the politics first.

Furthermore, despite the government’s assertions, our involvement will increase the short-term risk of terrorist attacks in Britain. As the attack on the Russian airliner showed, military actions can crystallise immediate terrorist responses. That is not a reason for inaction, but we should be honest with the British people about the consequences of what we do.

The reason for hesitation here is even more important. The Paris atrocity may just have created a strategic opportunity that will allow Isis to be completely eradicated. That will be in the first case a political initiative, the building of a grand alliance that creates both the plan and the military instrument to bring a stable future to this tortured part of the Middle East. Once that is done, then we should put our shoulder to the wheel, with every bit of military muscle we can muster.

But now? If we focus our efforts on providing a marginal military input in Syria, we will no doubt feel better about ourselves. Perhaps David Cameron will feel that he has put us back in the front rank of the alliance. It might provide some good short-term headlines. But we will have wasted what might be the best opportunity for 10 years to bring a real solution to the tragedy that is Syria and Iraq today.

David Davis is the Conservative MP for Haltemprice and Howden. He is a former shadow home secretary

Kholoud Waleed: Inside Syria

Girls on their way to school in Raqqa. Photograph: Reuters

I’m against the air strikes, as things stand, so British involvement will only add to the pain. Those who are paying in places such as Raqqa are the civilians. They are controlled and terrorised by Isis and are now suffering the effect of western bombs too. So they are paying twice.

I’m not convinced by the arguments that the coalition bombs are harming Isis – friends whose families are still in Raqqa do not tell it that way; they don’t welcome the bombs.

The best way ahead, for me, remains in first stopping the Assad regime and its advances, and hopefully turning places such as Aleppo into safe places. This would then allow the people of Raqqa to have a plan – they would at least have safe spaces they could attempt to escape to. No-fly zones should be created, holding back Assad’s forces.

I recognise that fleeing Isis is easier said than done, but I believe that the people can create their own ways. The alternative, at the moment, is to sacrifice the people of Raqqa. I genuinely feel that, given time and space, the people can begin to solve their own problems. But right now neither time nor space is available, and there are constant outside pressures. The anti-Assad forces are fragmented in part because of the various interests of their donors. It would be helpful if the Americans, Qataris and Saudis reminded the forces of their common goal.

The overwhelming sense I want to get across is for us not to get confused. It remains the case that if we want to stop Isis, first we have to stop Assad.

Kholoud Waleed is a Syrian activist, exiled in Turkey. (We have withheld her picture.)

Camille Frouin: The view from France

People pay their respects at the Place de la Republique in memory of the 130 victims of the Paris terrorist attacks. Photograph: Patrick Aventurier/Getty Images

Whether Britain should join in the air strikes is a question I will leave to those better qualified, but we young French really do appreciate the solidarity of the British. I’m just not sure that air strikes would be the only way to express solidarity. To go beyond debates about the political and military strategy, we recognise the British people as a key ally because they recognise shared moral values which go beyond the imperialist.

If we have to conduct wars, there are also social wars. These are not necessarily about intervention in foreign territories, but are played on a different terrain.

In France as elsewhere, we closed our eyes to the threats that have grown among us, to the point that today we refuse to perceive them as internal, hence the focus beyond our borders. The high state of security that’s been imposed here is a great way to comfort ourselves with the reassuring idea that the threat will always come from outside. But the truth is, perhaps, that our societies are incredibly fertile ground because they are fragile.

The war we have to wage is a daily one. Its weapon is the strongest and most dangerous in the eyes of our enemies – forging unity around the values of freedom, equality, fraternity. It was amazing to see in the last couple of weeks the speed at which our national motto spread as a slogan on social networks.

But now our daily war should be to go beyond the slogan – make these values clear again, restore to them a proper meaning. Today, too many people consider human rights as a utopia. We gladly apply our moral values to our small circle of close friends but we no longer think of them as a reachable goal for all.

So in France our motto now only unites us in moments of great collective pain, generalised pity. When the collective emotion subsides, we all return to our small concerns. Pity shouldn’t be the only spur for us to remember our values, though pity, I recognise, is at the base of our morality. Our war is that of breaking down barriers. This war belongs to everyone. It’s mine, it’s yours.

For my part, I am going to listen to Led Zep and drink a beer on a cafe terrace in the hope of living better. Hope is not a bad weapon. The solidarity of Britons, especially young Britons, is particularly important to us. It is a relief and a hope – it’s a weapon.

Camille Frouin is a student in history and political science in Lyon. She became known as part of the “Jeunesse du 13 Novembre”, after she wrote an emotional response to the Paris attacks in Le Monde

Anthony H Cordesman: Military view

A tornado fighter plane takes off from the British army’s base in the Falklands. Photograph: Lewis Whyld/PA

There has never been a clear reason for Britain to focus its air strikes only on Isis targets in Iraq. Isis operates as an entity across the border area of both Iraq and Syria. It cannot be defeated by striking at only half of its “caliphate”.

It is also clear that Iraqi ground forces, Kurdish forces and Arab rebel forces cannot liberate either western Iraq or eastern Syria without as much air support as they can possible get.

Moreover, air power is the primary weapon against the ability of Isis ability to take more territory, massacre more minorities, raise funds and create a growing force of foreign volunteers that threaten Europe as well as the states in the region.

This was also a real coalition long before the tragedy in Paris. To put the size of the coalition effort in perspective, it had flown 8,289 strikes as of 19 November – with 5,432 in Iraq and 2,857 in Syria. The US had dominated these strikes, 6,471 in Iraq and Syria (3,768 Iraq/2703 Syria). However,but the rest of coalition has carried out 1,818 attacks (1,664 in Iraq and 154 in Syria).

Britain’s action in Iraq were part of strikes by nine coalition countries alongside the US, Australia, Belgium, Canada, Denmark, France, Jordan and the Netherlands.

It would scarcely be alone, however, in joining the coalition effort in Syria – it would then share the burden with the US, Australia, Bahrain, France, Jordan, Saudi Arabia, Turkey and the UAE.

Britain would be able to take advantage of the massive intelligence surveillance, and reconnaissance capability, that the US has deployed, its refuelling and air transport capabilities, base security and support efforts. To put this effort in perspective, the coalition had flown 57,301 sorties of all kinds by 14 November.

It is also important to note, however, that while sorties can be flown against targets in Syria by any coalition air force, Britain would contribute some of the most effective aircrews and precision strike capabilities of any force in the world and its strikes would have maximum effectiveness with a minimal risk of civilian casualties. This is critical to both winning the support of the population on the ground and rebel factions, and to making air power truly effective.

Far more is involved than gestures of alliance solidarity and showing that the west cannot be intimidated by Russia, important as both goals are. As of 30 October, the coalition had flown 17,592 strike sorties supported by 8,012 intelligence surveillance and reconnaissance sorties. The problems in keeping civilian casualties to a minimum, and the problems in assessing targets in Syria and being certain that civilians would be protected as much as possible, meant that only 31% of combat sorties were able to release a weapon in the first 10 months of 2015.

The quality of British air power makes it far more critical than the number of future sorties alone can indicate.

Anthony H Cordesman is chair of strategy at the Center for Strategic & International Studies, Washington. He served as national security adviser to John McCain

Hassan Hassan: The Practicalities

A fighter from the Democratic Forces of Syria sits at a guard post in the town of al-Melabiyyah last week. Photograph: Rodi Said/Reuters

The importance of Britain’s involvement in the US-led international campaign against Islamic State should not be in doubt. The UK is already involved in the effort to support local Syrian forces in their struggle against the Assad regime. And it would gain from a closer engagement that would increase the British authorities’ knowledge of the conflict zones and help them deal with challenges that emerge out of these zones, primarily the challenges posed by Isis.

The real question for the UK should be how to break away from the current constraints to the international air campaign set by the US administration. Over the past few months, the anti-Isis effort has peaked and the size of local forces committed to the fight is shrinking. Also, Isis has better adjusted to the air strikes and the soft targets against the group were mostly eliminated in the early stages of the fight. Breaking the current stalemate will require more force but also wisdom than the first stage, which focused on militarily containing the organisation in some areas.

This could mean that, if David Cameron’s proposal is authorised, the UK will have arrived at a more critical point in the international effort. So in addition to whether the move should be authorised – which I hope will be the case – more focus should be given to how the UK can make a difference. As long as the UK operates in the shadow of the US, the anti-Isis campaign will remain in stalemate. If the UK joins, it ought to come with its own vision. This must centre on getting more local forces to buy into the effort of driving Isis out of Syria. In Obama’s words, the model that proved successful is a reliance on local forces “that can not only succeed against [Isis] but then sustain in terms of security and in terms of governance”. That is exactly what the UK should focus on and this requires deeper military engagement on the ground.

Britain’s greatest contribution to the fight on the ground would be to finesse the campaign. It is better positioned than other countries to do so through its connections with Syrian forces as well as its alliance with the US. Statements made by Cameron – about the number of moderate forces that could join the fight or that Assad is not the future for Syria – are positive signs that the UK might focus on working with local forces. The slow pace of the campaign is helping Isis adapt to the new reality. In some cases, the air strikes lead to unintended consequences. For instance, some people have been driven towards the organisation because of financial hardships after the campaign’s disruption of an economy that was functioning. The air campaign cannot drag on for too long, and a more effective approach is needed to mobilise enough local forces to take on Isis. This is where the UK can help.

Hassan Hassan is co-author of Isis: Inside the Army of Terror