A new phase of violence in Iraq and the dynamics of the conflict in Syria provide fertile conditions for the re-emergence of the al-Qaida idea.
The structure of the al-Qaida movement at its height was always far from the traditional hierarchy of many revolutionary bodies. But it did have a recognised leadership and a shifting geographical base which over two decades moved from Afghanistan to Saudi Arabia to Sudan, then back to Afghanistan  and (most recently) Pakistan.
Today, as a structured entity al-Qaida is clearly less formidable than before, and even as a more fluid movement it has lost momentum. But it endures as an idea and sense of mission: something apparent in different ways in north Africa, Yemen, Somalia and (most potently at present) in the form of the Boko Haram movement in Nigeria (see "Al-Qaida franchise: the Nigerian case ", 25 August 2011).
Yet of these developments, only Boko Haram  represents a new lease of life. This is what gives current developments in Iraq and Syria an extra potential significance. For there are indications that the aftermath of the eight-year war in Iraq and the dynamics of the conflict in and around Syria could fuel a further evolution of al-Qaida (see "Al-Qaida: an open endgame ", 12 January 2012).
The Iraqi descent
In Iraq, Nouri al-Maliki has survived as prime minister far longer than many expected and has now begun seriously to consolidate power. His power-base lies in the country's Shi'a majority which had been marginalised and excluded during the Saddam Hussein  regime. That experience of persistent mistreatment underlines the present government's determination to maintain control of the country at the expense of much of the previously powerful Sunni minority, as well as to clip as far as possible the Iraqi Kurds' extensive authority in the northeast.
A new assessment from the London-based International Institute for Strategic Studies  (IISS) is bluntly pessimistic. It contrasts expectations at the time of the United States withdrawal with outcomes:
"When the American military presence in Iraq ended in December 2011, Washington and Baghdad claimed that Iraq was a stable, sustainable democracy. However, this seems questionable as Nuri al-Malaki, prime minister since 2006, has continued his quest to dominate the state and to use its power to break opposition to his rule. His systematic exclusion of key politicians from power underlines the failure of the 2010 elections to deliver representative government, and leaves the country vulnerable to heightened sectarian tension and a new civil war" (see "Iraq: Malaki power grab risks fresh civil war ", IISS Strategic Comments, 20 April 2012).
Al-Maliki has done more than excluded politicians: he has targeted them for arrest, and his security personnel have tortured  associates to gain evidence against them. He is aided in his endeavours to entrench control by violent  opposition from Sunni paramilitaries, whose series of bombings and shootings (mainly in Shi'a areas and against Shi'a figures) reinforces sectarian-political divides.
The associated decay of prospects for democracy in Iraq is a condition favourable to the further re-emergence  of the al-Qaida idea there. The tendency of events in Syria, and the wider regional context of the deep antagonism between Saudi Arabia and Iran, are also relevant to this prospect.
The pattern of conflict
The Syrian rebellion is now in its second  year. Though it has not yet developed a marked sectarian dimension, it is clear that radical Islamist elements are working hard to influence the progress of the opposition to the Bashar al-Assad regime (see Liz Sly, "Fears of extremism taking hold in Syria as violence continues ", Washington Post, 23 April)
Much of this is centred on a group called the Jabhat al-Nusra which has claimed  responsibility for attacks on government buildings, most recently the bombing in Damascus on 17 March 2012 that killed twenty-seven people and injured ninety-seven (see Fay Ferguson & Hugo Wlliamson, "Factional fight - conflicting objectives in the Syrian struggle ", Jane's Intelligence Review, May 2012).
Perhaps most significant of all is the growing evidence that experienced paramilitary radicals are entering Syria, principally from Iraq, in order to join the rebellion and influence  its nature and direction. A high proportion may themselves be returning Syrians, while others are Iraqi and from elsewhere in the region. The absolute numbers are not yet greatly significant, but the phenomenon  has an important historical perspective that must be factored in.
In Afghanistan in the 1980s, some of the mujahideen fighting  against Soviet occupation went on to be part of the cohort of paramilitary Islamists that were so crucial to the early development of al-Qaida. Many of the latter were committed young men who had gained confidence and experience in fighting against the Soviet forces.
Twenty years later, a new generation of paramilitaries fought the coalition in Iraq. They acquired intense combat experience in an urban insurgency against the well-trained and very well-armed volunteer army and marine corps of the United States - a far more valuable encounter  than the one against low-morale Soviet conscripts in rural Afghanistan (see "Afghanistan: echoes of Vietnam ", 10 February 2011).
Most of those that survived the Iraqi crucible, probably amounting to thousands, returned to their own countries - or, if they were themselves Iraqis, continued to engage in some way in violent opposition to al-Maliki's regime.
It is they and their co-fighters from other theatres who are now crossing the border into Syria. A component of the mix of motivation and opportunity that guides them is awareness of the geopolitical  balance where the hated Bashar al-Assad regime has a very close relationship with Tehran and is thus strongly opposed by Iran's regional rival Saudi Arabia (see Madawi al-Rashid, "Saudi Arabia and Syria: logic of dictators ", 20 March 2012).
This pattern of alignments creates a risk that the Syrian conflict will evolve into a rebellion in which - as in Iraq today - a resurgent  al-Qaida ideology plays a prominent role. This is by no means inevitable, but the risk is reinforced by the deep Saudi-Iranian antagonisms and the influence of both countries in Syria and Iraq.
A situation so dangerously poised could yet be retrieved if some kind of compromise can be reached between Assad and the Syrian opposition; and, where any influence can be brought to bear, if Nouri al-Maliki's government can be persuaded that its rigid centralisation of power could have violent and counterproductive consequences. It is very late in the day for such negotiations, but conditions on the ground and the tensions between states alike add to the urgency.