Though the perpetrators have not yet been identified, the latest terrorist attack in Syria suggests that the non-violent and insurgent strands of the uprising could both be overtaken by a campaign of indiscriminate violence.
On Thursday 10 May, the fifth terrorist attack in five months, and the deadliest since the beginning of Syria's uprising, tore through the capital city of Damascus. Syria is supposed to be healing in the care of a ceasefire and peace plan overseen by former UN Secretary Genera, Kofi Annan, but these plans are looking more tenuous - indeed, illusory - with every passing day.
The evolution of Syria's uprising
Syria's uprising began as a peaceful pro-democracy protest movement over a year ago. It slowly acquired political accoutrements - notably, a political umbrella group called the Syrian National Council (SNC), a Turkey-based Free Syrian Army (FSA) of exiles and volunteers, and numerous other opposition institutions.
Under the pressure of a brutal government crackdown, centred on the use of elite troops with artillery and armour, parts of that movement morphed into an insurgency.
Some parts of that insurgency merely protected peaceful protests, whereas others mounted more offensive raids on government forces. The SNC, having committed to safeguard the ''peaceful character'' of the revolution, eventually gave up and sought to assist and (less successfully) lead its armed segments.
Now, with rising numbers of terrorist attacks directed at military institutions but causing substantial non-combatant casualties, there is the very real danger that the protest movement and the armed insurgency both become overtaken by a campaign of indiscriminate violence intended to sow sectarian discord, marginalise pragmatic parts of the opposition, and accelerate Syria's political disintegration.
Al Qa'ida, with Zionist-American backing
The Syrian government has attributed past bombings to al-Qa'ida, with 'Zionist-American' backing. Such claims are designed to reinforce the government's narrative of an onslaught by jihadists and foreign powers.
President Bashar al-Assad has cast himself as protector of his country's plethora of minority communities. As such, he wants to portray the opposition as little more than extremist Sunni terrorists, and stooges of the region's powerful Arab states.
Indeed both groups - Sunni fundamentalists and Sunni-majority Arab powers like Saudi Arabia and Qatar - have come out strongly against Assad's regime, for both strategic and ideological reasons. For the latter group, Assad's Syria represents Iran's major foothold in the Arab world and means of supporting the Lebanese Shia militant group Hezbollah. Qatar's ruler proposed sending troops to Syria last year (though had little means of following up on this pronouncement), and various officials in Saudi Arabia have advocated - and perhaps begun - arming parts of the Syrian opposition.
Moreover, many (though by no means all) middle-class urban Syrians continue to support Assad, or at least see his rule as preferable to what they assume would be conservative Sunni-majority rule, especially if such a successor regime were under the influence of the aforementioned Arab powers. Nir Rosen, a journalist who travelled around Syria, explains in his excellent overview of the role of Islamism that 'Syria's uprising is not a secular one. Most participants are devout Muslims inspired by Islam. By virtue of Syria's demography most of the opposition is Sunni Muslim and often come from conservative areas'.
Pro-Assad segments of the Syrian population sincerely see their state as pluralistic, secular and ultimately the only system by which the safety and rights of Syria's minority can be guaranteed. Islamists of all stripes, but particularly jihadists, and Sunni Arab states are both perceived as the antithesis to this supposed pluralism and secularism. Assad's message - that Syria is under siege - therefore resonates, and does so particularly loudly in the aftermath of such incidents.
False flag operation
By contrast, many members of the Syrian opposition have argued that these
bombings are the work of the government itself, in an effort to tarnish the opposition, deter foreign intervention, and win the loyalty of fearful minorities through heightening their fears.
Indeed, the timing of this and previous bombings has been suspect. December's attack occurred just as an Arab observer team arrived in Syria, as part of an ill-fated Arab League plan to end the conflict. These latest blasts came just one day after a roadside bomb nearly hit a team of UN observers who were traveling in a restive southern part of the country. The implication is that the government may be seeking to deter foreign observers from traveling too freely or expanding their mission, as UN Secretary General Ban Ki-Moon has advocated.
Moreover, Al-Qa'ida doesn't have a history of mounting attacks on Syrian soil. Sunni Islamists in Syria once waged a bloody six-year insurgency, but the regime's massacre at Hama in 1982 put an end to that. In 2008, a suicide bombing in Damascus killed 17 Syrians, yet the perpetrator was never clear.
The jihadist strand of Syria's opposition
However, we should be wary of the idea that these bombings are 'false flag' operations by the government.
American officials - who are hardly sympathetic to the Syrian government - have agreed that they see AQI-linked fighters as responsible for earlier bombings in Damascus and Aleppo, something reinforced by the method and targets of these attacks. From January onwards, a previously unknown group, the 'al-Nusra Battlefront', has claimed responsibility for various attacks (though not all).
In fact, Al Qa'ida and affiliated groups have both the motive and opportunity to exploit Syria's fraught sectarian balance, just as they did in Iraq in 2006. That year, the bombing of a Shia mosque in the city of Samarra sparked off a horrific civil war between (majority) Shia and (minority) Sunni.
Al-Qa'ida in Iraq (AQI) used both Syrian manpower and supply lines. Today, those resources are almost certainly being turned back into Syria. AQI made itself enormously unpopular in Iraq by unleashing untrammelled violence against Iraqi civilians. Now, it may see a fresh chance to gain credibility and support in a fight against President Assad's self-declared 'secular' government.
One counterterrorism expert, Brian Fishman, notes that 'we know that [Al Qa'ida leader Ayman] al-Zawahiri has given the green light to AQI to participate [in Syria]; he's done it publicly and may have done it privately beforehand. We know that the global jihadi community is much more forward leaning and aggressive when it comes to Syria as opposed to North Africa'.
That may be an especially attractive strategy at a moment when parts of the opposition are realising that no cavalry - whether NATO or the Arab League - is coming to rescue them.
Implications of the latest bombing
In the short-term, this bombing will not change the underlying tactics of the armed parties. The regime is continuing its crackdown. Moreover, it is ignoring crucial elements of the peace plan - such as withdrawing its forces from population centres.
The armed opposition, having lost key territories like Homs to government offensives, has shifted to guerrilla tactics. It is impossible to accurately assess the degree to which the opposition is still engaging in attacks on government forces today, and the degree to which such attacks are merely responding to prior government offensives. What is clear is that the rebels will not disarm so long as any political settlement looks fanciful.
More recently, non-violent protest has found more space. One possibility is that the most extreme parts of the opposition want to curb this form of resistance and ensure that the uprising remains wholly militarised.
But there is a broader problem here, which is that the opposition itself remains disunited both at the highest and lowest levels. The SNC itself has divisions, of course - for instance, Kurdish groups have been leaving its fold, and Alawites are not perceived to have proper representation.
But even if these divisions were repaired, this would not change the underlying fact that local fighters are neither part of a broader military command structure nor willing to subordinate themselves to a higher political authority. Some may be, but a great many will not. There will therefore always be parts of the opposition who follow their own strategy - no matter the presence of absence of a ceasefire.
Similarly, those parts of the opposition with an avowedly jihadist outlook will have every incentive to accelerate the breakdown of any political agreement and, indeed, to increase the level and spread of violence. Such groups are an unfortunate, small, but real and dangerous component of Syria's uprising.
Implications for foreign actors
The bombing will also place very severe pressure on the UN, which will be concerned for the safety of its staff. It may now be deterred from expanding the size and scope of its mission. Yet, the pitifully small numbers of observers inside Syria have no chance of covering and documenting the full range of violence in the country.
The dilemma for Western states is that they can see the Annan peace plan unravelling before their eyes, understand the basic futility of the observer mission, but are horrified by the prospect of becoming militarily involved in a conflict whose participants and details are growing dizzyingly complicated. As the New York Times noted this week, 'attention in Washington is increasingly focused on the opposition inside Syria, raising urgent questions about its motives, leaders and backers'.
The US would be loath to see weapons or other material support find its way to the most extreme parts of the opposition, and increasingly doubts that successful regime change would in fact bring a stable, democratic successor government. Moreover, these bombings remind policymakers that any US or international presence on the ground - even within a territorially delimited 'safe zone' - would be vulnerable to such attack - the most obvious precedent being the 1983 Beirut barracks bombing that killed 241 American servicemen. US officials insist that a UN Security Council Resolution is the prerequisite for intervention, but this is slightly beside the point - the problem is not on the supply-side (legal authorisation) but on the demand-side (political will to intervene, and the perception that intervention can in fact play a constructive, durable role).
Assad's regional adversaries - Turkey, Saudi Arabia, Qatar and other Arab states - have postured a great deal, but done very little. They are still waiting for US leadership - and they may be waiting a long time. President Obama has no wish to initiate a war merely months away from a national election, and European states are facing their own internal problems. A change of government in France, and political distractions in Britain, mean that neither state can take the lead and draw the US in as occurred over Libya last year.
The most insidious effect of this latest terrorist attack may be to widen the already severe sectarian fault-lines between Syria's Sunni majority (who dominate the uprising) and its anxious minorities, including the Alawite sect of the Assad family. That would have a highly destabilising effect on the country as a whole and its politically fragile neighbours, Iraq and Lebanon.
The activities of jihadist groups in Iraq demonstrated the politically corrosive and unpredictable effect that such frequent bombings can have on a state and its social fabric. The growth of the jihadist strand of the opposition could derail not just the peace plan, which is likely to collapse soon enough anyway, but also the democratic aspirations and limited cohesion of the Syrian opposition.
 Raymond Hinnebusch, 'Syria: From 'authoritarian Upgrading' to Revolution?,' International Affairs (Vol. 88, No. 1, January 1, 2012), pp.95-113.
 Emile Hokayem, 'Syria and Its Neighbours,' Survival (Vol. 54, No. 2, 2012), pp.7-14.
 Christopher Phillips, 'Syria and Iran: Diplomatic Alliance and Power in the Middle East,' British Journal of Middle Eastern Studies 38, no. 3 (2011): 439-441.
 Eric Schmitt and Thom Shanker, 'Al Qaeda Influence Suspected in Bombings in Syria,' The New York Times, February 15, 2012, http://www.nytimes.com/2012/02/16/world/middleeast/al-qaeda-influence-suspected-in-bombings-in-syria.html.
 Mohammed M. Hafez, 'Suicide Terrorism in Iraq: A Preliminary Assessment of the Quantitative Data and Documentary Evidence,' Studies in Conflict & Terrorism 29, no. 6 (2006): 591-619; Brian Fishman, 'After Zarqawi: The Dilemmas and Future of Al Qaeda in Iraq,' The Washington Quarterly )Vol. 29, No. 4, 2006), pp.19-32.