DOUMA, SYRIA - FEBRUARY 02: A Syrian man takes his son away after Syrian regime's air forces' air attack on East Ghouta region with 'Vacuum Bomb' that killed at least 10 people and injured 75 others in Douma, Syria on February 02, 2015. (Photo by Yousef Albostany/Anadolu Agency/Getty Images)

The global powers that met two times in Vienna for landmark discussions on ending the war in Syria may meet again in New York this month while several hurdles remain. In a March 2015 op-ed for the National Interest, I proposed a six step plan with 10 principles to resolve the Syrian conflict. During the past two years, I have sought to promote this proposal in numerous international seminars and conferences.

In late October, the International Syria Support Group agreed in Vienna on principles virtually identical to my six step proposal. In a joint communique issued after the conclusion of the talks, the participants agreed on the following:

1. Syria's unity, independence, territorial integrity, and secular character are fundamental. 2. State institutions will remain intact. 3. The rights of all Syrians, regardless of ethnicity or religious denomination, must be protected. 4. It is imperative to accelerate all diplomatic efforts to end the war. 5. Humanitarian access will be ensured throughout the territory of Syria, and the participants will increase support for internally displaced persons, refugees, and their host countries. 6. Da'esh (Islamic State), and other terrorist groups, as designated by the U.N. Security Council, and further, as agreed by the participants, must be defeated. 7. Pursuant to the 2012 Geneva Communique and U.N. Security Council Resolution 2118, the participants invited the U.N. to convene representatives of the Government of Syria and the Syrian opposition for a political process leading to credible, inclusive, non-sectarian governance, followed by a new constitution and elections. These elections must be administered under U.N. supervision to the satisfaction of the governance and to the highest international standards of transparency and accountability, free and fair, with all Syrians, including the diaspora, eligible to participate. 8. This political process will be Syrian led and Syrian owned, and the Syrian people will decide the future of Syria. 9. The participants together with the United Nations will explore modalities for, and implementation of, a nationwide ceasefire to be initiated on a date certain and in parallel with this renewed political process.

During their subsequent meeting in November, the ISSG elaborated on the specific phases of a conflict resolution plan that echoed those I laid out in my March op-ed. The differing side agreed on a Jan. 1 deadline to form a broad-based forum comprised of President Bashar al-Assad's government and opposition groups. The forum agreed to establish within six months, a "credible, inclusive and non-sectarian" transitional government that would determine the schedule for drafting a new constitution. Within 18 months, a free and fair U.N.-supervised election will also be held.

Moreover, the ISSG agreed that the violence in Syria should come to an end through a cease-fire in "parallel" to the process of political transition.

These are all remarkable achievements and represent a major step towards the resolution of the tragic war ravaging Syria today. However, there are still three major obstacles in the path of a diplomatic solution, but they should not prove to be insurmountable.

Obstacle 1: What to do with Assad

President Putin shakes hand with President Assad in Moscow. Alexei Druzhinin, RIA-Novosti, Kremlin Pool Photo via AP.

The first expectedly has to do with President Bashar al-Assad. The United States, Russia, Iran, Turkey and Saudi Arabia, the five major international and regional powers with influence in Syria, sharply diverge on the issue of Assad's future in Syria. The Saudi-U.S.-Turkey coalition's priority is the removal of Assad, whereas Iran and Russia's is to first eradicate from Syria the terrorist organizations that have occupied some 50 percent of the country and then to hold free elections monitored by the United Nations to decide the country's president and constitution. For its part, Iran has maintained for years that it is the Syrian people who should decide on who their president should be, not other countries.

After the ISSG Vienna meeting, President Barack Obama declared: "Russia and Iran must decide whether they want to prop up Syrian President Bashar Assad or save the Syrian state." However, the experience of Libya these past few years shows that Obama is wrong. NATO and its Arab allies attacked Libya, overthrew Qaddafi, and have since then sat totally helpless as the country has descended into chaos and come to the verge of being a failed state.

It is has already been agreed in Vienna that "Syria's unity, independence, territorial integrity, and secular character are fundamental" and that its "state institutions will remain intact." It is difficult to imagine how the collapse of Assad would not portend the total collapse of the security-military establishment of Syria. And without the current Syrian military and security forces -- which are the most consequential force on the ground fighting terrorist groups like the self-proclaimed Islamic State, Al Qaeda and Jabhat al-Nusra -- it would be impossible to preserve the territorial integrity of Syria. Indeed, in the fight against terrorism in Syria, the insurgents supported by the West and its Arab allies like the Free Syrian Army have been almost completely ineffective.

Therefore, the critical priority should be to clear Syria of terrorist groups, reestablish the country's territorial integrity, create the conditions for the return of displaced persons and refugees, and then leave it to Syrian people to choose their leadership through transparent, free and fair elections within the framework of a new constitution that enshrines protections for all minorities.

Obstacle 2: How to effectively fight terror groups in Syria

The Paris massacre and threat of further ISIS attacks abroad underscore the importance of this cooperation. AP Photo/Militant Website, File.

The second key obstacle to a sustainable peace in Syria has to do with how to effectively fight and destroy terrorist groups in the country like ISIS. The fact is that airstrikes are only effective when conducted in support of a well-organized military partner on the ground. In Syria, the largest and most effective ground force fighting ISIS and other terrorist groups is the Syrian military, which is supported by Russia and Iran. Regional U.S. allies, on the other hand, have been supporting many of the terrorist groups fighting the Syrian army.

The United States and its allies need to understand that it is impossible to fight ISIS and the Assad government simultaneously. To form the necessary coalition of air and ground forces to destroy ISIS, cooperation between NATO, the Syrian army, Russia and Iran is vital. The Paris massacre and threat of further ISIS terrorist attacks abroad makes such cooperation even more necessary and politically viable.

Obstacle 3: Extremist movements' ties to West's allies

Extremist Sunni movements draw their ideology and the vast majority of their weaponry and financial support from the closest allies of the West in the region. AP Photo/Hasan Jamali.

The third dilemma is the reality that extremist Sunni movements such as Al Qaeda, ISIS and the like draw their ideology as well as the vast majority of their weaponry and financial support from the closest allies of the West in the region. It is time to realize that because ISIS is first and foremost an ideology and culture, not merely a militia, the world will never be able to defeat it as long as Western allies are actively promoting its ideology.

As former U.S. Ambassador Curtin Winsor, who was special emissary to the Middle East at the beginning of the Reagan administration, wrote in 2007:

The Saudis have spent at least $87 billion propagating Wahhabism abroad during the past two decades ... The bulk of this funding goes to the construction and operating expenses of mosques, madrassas, and other religious institutions that preach Wahhabism. It also supports the training of imams; domination of mass media and publishing outlets; distribution of Wahhabi textbooks and other literature; and endowments to universities. By comparison, the Communist Party of the USSR and its Comintern spent just over $7 billion propagating its ideology worldwide between 1921 and 1991.

The first day that Russia launched military strikes against terrorist groups in Syria, a prominent citizen of a U.S. ally in the region told me at a conference in Berlin, "we will make Russia bleed." The blowing up of a Russian passenger plane claimed by ISIS and a Russian military jet by Turkey are steps in that direction.

What the major Western powers need to keep in mind is that their efforts in the past few decades to transform certain countries through military and political intervention have failed. In Syria, this approach has led to a "secular" political order coming to the edge of being overthrown in favor of a Salafi-Wahhabi Islamic state taking control of the country. Until this approach is abandoned in favor of pragmatism, the war on terror will not end and terrorist attacks in the West and elsewhere will continue.

Ambassador Seyed Hossein Mousavian is a research scholar at Princeton University and former deputy of Iran's national security foreign policy. His latest book, "Iran and the United States: An Insider's View on the Failed Past and the Road to Peace" was released in May 2014.

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