Diplomatic negotiations on Syria got lost in the aftermath of the Paris attacks a week ago. But the talks have made surprising progress -- and they may prove a crucial part of any successful strategy for combating terrorists from the Islamic State.

Secretary of State John Kerry managed to gather all the major players -- Russia, Saudi Arabia, Iran, Turkey and the key European nations -- in Vienna last weekend. Just getting them to the table is an accomplishment -- and a move back from the Saudi-Iranian proxy war that has helped drive the Syrian nightmare.

The next step would be a cease-fire between the regime of President Bashar al-Assad and the nonterrorist opposition. Such a truce would allow a multipronged assault on the Islamic State and Jabhat al-Nusra, the al-Qaida affiliate in Syria. Here, too, there has been unexpected progress.

A test of the delicate process will be whether it includes an Islamist opposition group called Ahrar al-Sham. This rebel group has been backed by Turkey, Qatar and Saudi Arabia, and it has fought alongside Jabhat al-Nusra against the regime and its Russia ally. But, interestingly, the U.S. and the Assad government both seem willing to allow Ahrar al-Sham into the non-extremist tent, so long as it agrees to accept a cease-fire.

“If you come to the party, then you’re on the guest list,” says one source who’s close to the Assad regime. A similar thought is expressed from the other side of the conflict by one Gulf official: “If there’s a cease-fire, then whoever continues to fight will be on the ‘red list.’”

Ahrar al-Sham knows that it’s facing a significant decision. In Internet messages highlighted by the SITE Monitoring Group, an unidentified Jabhat al-Nusra fighter warned: “To Ahrar Sham: Soon the world will force you to fight the mujahidin or be labelled terrorists ... so pick your side.” An Ahrar al-Sham fighter named “Ladqani” wrote: “#AhrarSham One side accusing you of extremism, the other side of nationalism. And that’s how you’re treated when you take the middle path.”

Four years of war seem to have convinced some in the regime and in the opposition to accept the reality that neither side can win, and of the need for a truce that would bring a period of de facto partition into what politely could be called cantons. “After a cease-fire, the (U.S.-backed) Free Syrian Army gets to run its territory; the regime knows it can’t run that territory,” explains the source who’s close to the Assad regime.   

On the way to a national truce, there are attempts to negotiate local cease-fires, with mediation by the U.N. special envoy for Syria, Staffan de Mistura. These discussions have had little success so far, but the Assad regime is said to believe that it may be able to negotiate with some of the groups in southern Syria, where the opposition has strong links with Jordan.

Diplomats have also discussed ways to get Hezbollah and Iraqi Shiite militias out of Syria. One approach would allow the regime to get support from foreign militaries, such as Russia’s, or even Iran’s, to support the regime, but not foreign militias. The Syrians and Iranians are said to be willing to consider such a formula. According to U.S. and Arab sources, there’s some friction in the trilateral alliance of Russia, Iran and Syria -- adding to the current interest in a diplomatic settlement.

If a cease-fire can be negotiated, the next issue will be political transition, starting with parliamentary elections and moving, sometime down the road, to the election of a new president to replace Assad. To finesse this transition, diplomats favor a plan to increase the power of parliament -- and also, regional governments in a more federal Syria -- and a corresponding diminution of the president’s power. That might make it easier for the opposition to swallow Assad’s continuation in power during the transition.

Getting Syria’s feuding opposition groups to agree on a common program is as hard as getting Saudi Arabia and Iran to the table. But this effort, too, is moving forward. The U.S., Russia and Arab countries are all circulating lists of opposition politicians they favor in an eventual negotiation. It’s a cumbersome process.

What’s encouraging for now isn’t that all this Syria diplomacy is succeeding, but that it’s taking place at all.

By David Ignatius 

David Ignatius’ email address is davidignatius@washpost.com.--Ed.

(Washington Post Writers Group)