Is the Middle East heading for a full-blown religious war?

Are recent events in Syria the beginning of a wider conflict between Shias and Sunnis, or merely another stage in the regional political changes begun by the Arab spring?

Peter Beaumont
The Observer, Saturday 8 June 2013 

"Nine days ago the influential Sunni cleric Yusuf al-Qaradawi denounced the Lebanese Shia Hezbollah movement – whose fighters helped Bashar al-Assad's regime retake the Syrian city of Qusair last week – as the "party of Satan".
Speaking in Doha not long before Qusair's fall, Qaradawi did not stop there: the cleric, whose speeches and sermons are heard by millions, went a dangerous step further, calling on Sunni Muslims with military training to support the Syrian uprising against Assad.
It was a sermon that not only marked a sharp shift in the sectarian tensions in the Middle East between Sunni and Shia but an escalation in Qaradawi's own rhetoric. When I heard him preach on Syria at Cairo's crowded al-Azhar mosque last autumn, he was sharp in his condemnation of the Assad regime, but stopped short of endorsing a jihad.
In Doha, however, Qaradawi's remarks embraced a more dangerous sectarian notion. "The leader of the party of the Satan comes to fight the Sunnis … now we know what the Iranians want … they want continued massacres to kill Sunnis," Qaradawi said. "How could 100 million Shias defeat 1.7 billion [Sunnis]? Only because [Sunni] Muslims are weak."
Qaradawi's comments – endorsed last week by Saudi Arabia's grand mufti, Abdul Aziz al-Asheikh – did not come out of nowhere. They were a direct response to a speech made by Hezbollah's general secretary, Hassan Nasrallah, in Beirut, not only admitting that his fighters were in Syria but pledging that his men would help Assad – a member of the Shia Alawite sect – to final "victory".
If ever evidence was needed of the escalating sectarian dimension to the growing regional instability in the Middle East – in which the worsening conflict in Syria is playing a large part – it was visible last week.
It is visible in the rubble of Syria's Qusair, emptied now of much of its population, and taken by a joint force of Hezbollah and Assad government forces, as well as in Lebanon's seaside city of Tripoli, the country's second largest, where gun battles between Alawites and Sunni militias are continuing.
It has been visible, too, in Iraq, where lethal tensions, in part inspired by Syria but more largely by the country's own political tensions, have been growing almost by the week, witnessing more than 1,000 deaths in May, the highest monthly toll since 2008....."