Syria is at the nexus of two of the Middle East´s central problems: sectarian and ethnic rivalries and the Arab-Israeli conflict. Between that and its ties to anti-Israel groups like Hezbollah and Al Qaeda- inspired groups, as well as a three-decade alliance with Iran, the fallout from its uprising is likely to ripple, in unpredictable ways, throughout the region. Here´s a brief guide to the actors in the conflict:

The Assad regime

After 14 months of rising violence, the regime of President Bashar al- Assad has shown no sign of disintegration. Only a handful of minor officials have defected. Mr. Assad has been bolstered by diplomatic and logistical support from Russia, China, and Iran, as well as by the West´s reluctance to intervene militarily.

The regime also can rely on support from the minority Alawite community. At 12 percent of Syria´s population, many Alawites fear persecution or worse at the hands of majority Sunnis if the regime falls. This also explains why key units of the Syrian Army have held together. The well-equipped, well-trained 4th Armored Division is about 80 percent Alawite. For them, the struggle to crush the opposition is potentially an existential one. But even if the regime holds on, it is certain there will be no return to the Syria that existed before the uprising began in March 2011.

The Syrian opposition

The opposition is split between the exiles and the internal actors. The Istanbul, Turkey-based Syrian National Council is the leading platform for the opposition; but it has a troubled history of infighting and division, chiefly between Islamists and secularists. Burhan Ghalioun, the leader of the SNC, resigned May 24 in the face of mounting criticism.

The internal opposition is on the front lines of the struggle and has risked arrest, torture, and death. They view the external opposition with contempt and suspicion. The inability of the external opposition to provide a unified vision of a post-Assad Syria has seriously weakened its credibility inside the country, particularly among the minorities who so far have been reluctant to join the struggle.

The Free Syrian Army

The Free Syrian Army is the main armed opposition and consists of several "brigades," "battalions," and "companies." The strength of each unit runs from as few as 15 fighters to the Khaled bin Walid Brigade in the area of Homs, which boasts 3,000 combatants in five battalions. The leadership of the FSA is in Turkey, and most units act with a high degree of autonomy. There is some coordination between adjacent units, but the FSA essentially operates as a cellular guerrilla network rather than a regular army.

The FSA lacks regular supplies of ammunition and appropriate weapons, notably antiarmor missiles.

Foreign fighters

The Assad regime blames the violence on "armed terrorist gangs" sponsored by Saudi Arabia and Qatar and says Al Qaeda is operating in the country. Several large-scale bombings in Damascus and Aleppo have been claimed by a previously unknown jihadist group called the Nusrat Front. The Syrian opposition says the regime carried out the attacks to bolster its claim that Al Qaeda is present in Syria.

Ayman al-Zawahiri, Al Qaeda´s leader, has called upon Muslims to go to Syria and fight Assad. While there is credible evidence to suggest that elements of the armed opposition are inspired by religion, a formal Al Qaeda presence is unconfirmed. There is anecdotal evidence of foreign Arab fighters entering Syria to join armed groups. (See related story, page 21.) They include nationals from Lebanon, Iraq, Jordan, Tunisia, Algeria, Saudi Arabia, and perhaps Libya.

Religious and ethnic minorities

Christians, Druze, and Kurds generally have stayed out of a confrontation that pits the majority Sunnis against the minority but powerful Alawites. Many Christians, in particular, fear that the fall of Assad could usher in a Sunni Islamist regime that may restrict their freedoms. Syria´s minorities have watched neighbors Lebanon and Iraq tumble into civil war in recent years and have no wish to see Syria plunged into the same kind of conflict. (© The Christian Science Monitor. 06/07/12)