Syria is being wracked by two wars. One, between Syrian President Bashar al-Assad and rebel groups like the Free Syrian Army, can be resolved only through a diplomatic solution – precisely the kind of solution that the peace talks in Vienna, involving a wide range of world powers and regional actors, are aiming to reach.

The second, being waged by the Islamic State, will require a different approach.

Of course, the Islamic State’s war is, in a sense, also a civil war – both between Sunnis and Shia and among Sunnis – and it is related to the struggle against Assad. But the Islamic State’s brutal terrorist attacks in Beirut and Paris (not to mention its fighters’ barbaric behaviour within Syria and Iraq) make plain that there can be no talking to – much less compromising with – its leaders. No political, diplomatic, or territorial arrangement with such a group – whose fanatical ideas and vicious practices clash with all civilised societies’ fundamental norms – can be justified.

To be sure, diplomacy will be needed in this fight. Just as war is often an element of diplomacy, diplomacy can sometimes be an element of war. In the war against the Islamic State, diplomacy will be vital to galvanise an alliance of countries dedicated to the group’s complete eradication.

The Islamic State has no legitimate role to play anywhere. Anyone, especially in the region, who attempts to parse the group’s objectives – in order, for example, to support its anti-Shia aims, if not its methods – does not belong in the fight. To paraphrase President George W. Bush, countries have a decision to make: they are either with us or they are with the terrorists.

This is not just a matter of presenting a united front. As much as some would like to pin the blame for fueling Islamic State’s rise on the failure of Iraq’s Shia leaders to engage in sufficient Sunni outreach, this explanation is far from complete.

If the Islamic State were simply a vehicle for Sunni struggle against Shia rule, the conflict would not have expanded well beyond Shia-populated areas. The Islamic State is inspired largely by a radical and corrupted version of Wahhabism, the ultra-conservative Sunni sect embraced by Gulf monarchies like Saudi Arabia.

It is time for the Sunni Muslim world to act more resolutely toward the brutal movement that it has, intentionally or not, helped to spawn. To that end, Saudi Arabia must reverse its recent decision to turn its wrath against the Shia Houthi rebels of Yemen, rather than the Islamic State.

As for the civil war between Assad and his opponents, the Vienna talks offer reason for cautious optimism. The talks are not the beginning of the end of the Syrian conflict; they may not even be, to paraphrase Winston Churchill, the end of the beginning. But they amount to a serious step toward a much-needed diplomatic approach to resolving this aspect of the conflict – not least because many of the right players, from the US and the European Union to Turkey and Saudi Arabia, are participating in the process.

Still, the talks are far from perfect. Although it is too early to be critical of the effort, it is not too soon to highlight some potential concerns.

For starters, while elections are a laudable objective of the talks, they should not be the only one. Syria has many minorities whose numbers are too small to secure representation through the ballot box, and thus need to be protected by other means, such as political arrangements and institutions seeking to guarantee minority rights.

The first pillar of democracy may be majority rule, but it is a hollow and unstable achievement if the second pillar, minority rights, is not also put in place.

Another concern stems from the proclamations by several participants that the conflict-resolution process should be "Syrian-led.” A good idea, but it lacks merit. There is nothing in the behavior of any of the Syrian factions that have been fighting for the past four years to suggest that they are equipped to lead a peace process.

In times of crisis, countries have a way of forgetting the lessons of past crises. This month marks the 20th anniversary of the signing of the Dayton Accords, which ended the Bosnian War. That momentous step, which ended a brutal conflict in which civilians were targeted, emerged from a two-step process.

First, an international "contact group” agreed on aframework for peace. Then, the warring parties were brought in to reach agreement within the framework.

That may sound patronising, but it worked. Rather than getting distracted by some sense of wounded pride, those who have engaged in a conflict that has killed or wounded thousands of innocent people and displaced millions more should decide to do what it takes to end the mayhem.

Christopher R. Hill, former US Assistant Secretary of State for East Asia, was US Ambassador to Iraq, South Korea, Macedonia and Poland