After months of delay the Pentagon has declared that the Islamic State (also referred to as Isis) must be confronted in Syria, its main base, as well as Iraq.
US defence secretary Chuck Hagel called Isis "an imminent threat to every interest we have", whether in Iraq or elsewhere. He also admitted that the Isis threat could be larger than that posed by al-Qaeda itself.
Isis is a far greater geographical threat than al-Qaeda central.
While it is confined to the distant Afghan-Pakistan border, Isis is based in the heartland of the Middle East, the backyard of Europe and a major oil exporter.
It also has a more extreme religious ideology than al-Qaeda that appeals to disaffected Muslims in many countries.
Isis has recruited thousands of fighters from the Arab world, Africa, the Caucasus, Asia and Europe as well as a few score from the US. These numbers have risen from 10,000 to up to 50,000 because Isis has been successful on the battlefields of Syria and Iraq.
Unlike the hundreds of militias fighting in Syria, Isis is a solid organisation with a hierarchical structure, an administration that includes courts and effective command and control over forces.
Isis has arms captured from the Syrian and Iraqi armies, funds, and external sponsors including Qatar and Saudi Arabia and wealthy Kuwaitis.
Isis is parasitical and relies on manpower and support from local Sunnis seeking redress from regimes they believe rule on behalf of Shias.
Educated Isis members run an effective public relations operation involving dedicated websites and social media.
Isis is also a business that publishes detailed annual reports on its activities, including assassinations, bombings, shootings and attacks with the aim of soliciting funds and recruits.
Isis uses extreme measures – beheadings, torture, rape and communal cleansing – to terrorise those who refuse to submit to its rule or are regarded as “infidels”.
Britain is anxiously seeking the identity of a national who decapitated US journalist James Foley in Syria while other European countries are taking legal action against citizens who join Isis ranks.
So far, only one Isis veteran has carried out an operation in Europe: in May at a Jewish museum in Brussels. Mehdi Nemmouche, a French citizen of Algerian origin, was arrested.
Further attacks are likely with the return home of indoctrinated and trained veterans, retaliating for strikes by US warplanes on Isis cadres and convoys in Iraq and Israel’s latest bombardment of Gaza.