(Published in The Conversation in a subsequently updated version.)

In his 2014 State of the Union address, President Obama noted that the threat from al-Qaeda had evolved with affiliates of the terror group taking root in places as diverse as Yemen, Somalia, Iraq, and Mali.

The following day, the US director of national intelligence, James Clapper, told the Senate Intelligence Committee that Syria’s al-Nusra front, which has close links with al-Qaeda, was planning to attack the United States. With definitions of who is or is not al-Qaeda or an affiliate varying and the reasoning behind U.S. threat assessments is often vague, it was no surprise that Clapper did not offer any further details on the group’s alleged plans.

Yet, it is a long-known and well-established fact that a large number of foreign fighters from the Middle East, from Europe and – to a lesser extent – from the US are being trained in Syria now. The exact numbers of these fighters – and their origins – remain disputed, ranging from 7,000 to 11,000. The fear is, of course, that these fighters will eventually return home, not only more radicalised but also trained and more capable to carry out terrorist attacks.

The presence of foreign fighters in such local struggles, however, is not a new phenomenon. The origins of al-Qaeda in the 1980s are closely connected with the Mujahedin who fought against the Soviet invasion of Afghanistan. Foreigners who fought in these battles later on became part of what one might call a first wave of proliferation of jihadists.

Prominent examples of this initial spread of a “global” network of al-Qaeda affiliates can be found now in south-east Asia from southern Thailand (Gerakan Mujahadeen Islam Pattani) to Indonesia (Jemaah Islamiyah) and the southern Philippines (Abu Sayyaf Group); in Central Asia (Islamic Movement of Uzbekistan); and across North Africa (Moroccan Islamic Combatant Group).

Other battles that first attracted – and then dispersed – foreign fighters include: Bosnia (1992-1995), Chechnya (especially in the second half of the 1990s), Kosovo (1998-1999), Iraq (after 2003) and post-Soviet Afghanistan, during the civil war in the 1990s and after 9/11.

The fundamental difference between all these battlegrounds and Syria is the increasing number of fighters from western countries and hence the heightened sense of a renewed threat to Western homelands emerging as a result from their presence.

The current second wave of regional proliferation is more directly connected to recent conflicts in the Middle East, such as Iraq and the various Arab Spring uprisings. The connections between them are most obvious in the case of Syria where a network of al-Qaeda affiliates now reaches from Iraq to Syria and into Lebanon and has begun to expand further into Turkey, prompting further fears that Turkey might get dragged deeper into the violence in neighbouring Syria.

Al-Qaeda now has a much more entrenched presence in the Eastern Mediterranean-including in Syria, Lebanon, and Egypt-increasing the risk of direct strikes at Israel.

At the same time, the Arab Spring has given some groups something like a second lease of life: al-Qaeda in the Islamic Maghreb (AQIM) and al-Qaeda in the Arabian Peninsula (AQAP) both predate the turmoil in the Arab world after 2011, but have been able to benefit from the opportunities that these upheavals created in the Middle East and North Africa.

Yet regional proliferation does not stop there. Boko Haram, a northern Nigeria-based group of violent Islamic extremists, is said to have links with both AQIM and Somalia’s al-Shabab thus creating a situation in which al-Qaeda’s reach, through its various affiliates now extends across the whole of North Africa and the Sahel zone into West Africa.

Likewise, there is a fear that the presence of Indonesian militants in Syria will lead to a resurgence of violent jihadism potentially across all of southeast Asia.

The capacity of the various off-shoots of al-Qaeda varies greatly and not all of them have an agenda beyond narrowly defined local concerns, let alone plans to strike at western targets. But the sum total of the means and opportunities available to al-Qaeda to pursue global jihad has certainly increased as a result of the proliferation of affiliate groups.

This is partly due to the fact that a number of these groups control swaths of territory, at times significant areas, that can serve as safe havens, bases, and training camps. In addition, the regional proliferation of al-Qaeda affiliates has also increased and diversified fund-raising opportunities. Many of these groups have links to local and transnational criminal networks, such as in Syria, the Maghreb and West Africa, and Central and South Asia.

Beyond merely contributing to funding terrorist activities, links with transnational organised crime also provide important logistical support by potentially assisting in the smuggling of terrorist operatives, arms and equipment.

There also appears to be a shift in local tactics on the part of al-Qaeda to make it more amenable to its host communities. Once the group was considered its own worst enemy because of its advocacy for, and imposition of, harsh Islamic rule and the repression and persecution of non-Muslims in areas under its control, as well as the ruthless targeting of fellow Muslims seen as collaborators or apostates. As a result of this, al-Qaeda rarely managed to sustain broad public support in areas where it was active.

This became obvious when al-Qaeda was driven out of Iraq with the help of Sunni tribes in 2007-2008 and is apparent again in the current Sunni backlash against the organisation. AQIM faced similar problems in Mali in 2012-2013 and the civil war in Syria for some time has had a second front with secular and more moderate Islamist forces standing up to the Islamic State of Iraq and the Levant (ISIS).

But what appear to be new orders from the al-Qaeda leader, Ayman al-Zawahiri, that organisations affiliated with al-Qaeda should no longer target fellow Muslims but refocus their efforts on striking at the US and Israel, and presumably, although not specifically mentioned, western Europe.

This does not imply an immediate terror attack at anything like the scale of 9/11, but it is an unwelcome reminder that al-Qaeda’s jihadist agenda must remain a cause for concern.

Al-Qaeda may not have regained the global threat potential that it posed a decade or so ago – at least, not yet. But its local and regional efforts have made it, in many cases, a powerful and entrenched source of instability. If left unchecked, such local and regional power can grow into something altogether more terrible.