Editor's note: Charlie Cooper is a researcher on the Middle East at Quilliam, a think tank formed to combat extremism. The opinions in this commentary are solely his.
(CNN) -- Last night, a video emerged of the execution of American journalist Steven Sotloff, at the hands of Abu Bakr al-Baghdadi's ISIS, the extreme jihadist group that has illegitimately declared the establishment of a militant "caliphate" in Syria and Iraq.
This latest execution video follows that of a similar crime committed against another U.S. journalist, James Foley, a fortnight ago. Like the first "Message to America," this latest video ended with the executioner threatening to behead another captive non-combatant, this time a Briton.
First and foremost, it is imperative that we do not allow the traction that these videos have gained in the West to eclipse ISIS's other inhumane actions.
In years gone by, ISIS -- which refers to itself as the Islamic State -- and its forebears have consistently and persistently committed the most atrocious of war crimes against communities in the Middle East.
These come on top of the wholesale massacre it committed against the Sunni peoples of the Shu'aytat tribe in East Syria in August, as well as countless other summary executions of people it deems to be its enemies.
We must not be fooled into thinking that ISIS only beheads its Western captives; last week, a Kurdish man - unarmed, of course - was executed in front of a mosque in Mosul in a video entitled "A message written in blood." But because it was directed at the president of Iraqi Kurdistan, this particular piece of propaganda did not receive widespread coverage in the international media.
A cursory glance at ISIS propaganda suggests that the West is its primary target. While this may be the case in terms of the group's long-term ambitions, events on the ground in Syria and Iraq paint a very different picture, with ISIS predominantly killing those it deems to be "apostate", including its co-religionists.
In light of events in Syria and Iraq, the international community must react robustly and swiftly. This week's NATO summit is fortuitously timed, and one would hope that the ISIS crisis takes its place at the top of the meeting's agenda.
However, as I've said before, a strategy of solely Western intervention would play right into the ISIS ideology. Indeed, it would be exactly what the group wants. As such, it is paramount that other states -- particularly those within the region -- step up to the plate as well. Countries such as Turkey and Saudi Arabia must actively respond instead of leaving it to others.
It is not just the international community that has a responsibility, though: the media must act as well. It is paramount that it carefully considers its treatment of ISIS propaganda, with its twin aims of intimidation and recruitment.
Every time a still or clip from an ISIS video is shown, the group gets what it wants: the oxygen of publicity. Of course, it is necessary that people the world over are aware of the atrocities occurring at the hands of ISIS, but journalists must be careful not to do the jihadists' job for them.
This also involves establishing a firm no-platform policy for al-Baghadi's stooges in the West. These insidious individuals thrive on media attention, which they use to amplify their otherwise ostracized voices.
As Quilliam's last report, which looked at extremist content online, showed, it is an unfortunate truth that online censorship does not work.
Any attempts at censorship in the aftermath of the Foley killing were always doomed to failure. Simply put, corporations and governments are unable to remove propaganda from the internet at the rate that it is uploaded. More effective than government-led censorship was the "ISIS media blackout," in which users across the internet resolutely refused to publicize ISIS material. After all, videos like these have minimal propaganda value if they have no audience.
At the same time, instead of publicizing what ISIS wants, we must popularize what it doesn't.
The anti-ISIS fatwa recently released by prominent Sunni British imams would be a good place to start, because it dismantles any sense of legitimacy for the self-proclaimed "caliphate" and directly calls for Muslim communities to take an active stance in opposing this appalling group.
More initiatives like this must emerge. That they have not materialized already is testament an untenable situation in which the vast majority of Muslims, who are invariably moderate, are largely silent, something which leaves extremists to dominate the discourse on Islam.
The time has passed when we can allow ISIS to popularize itself unchallenged. Challenging ISIS propaganda must be at the forefront of international policy towards Syria and Iraq. And it is not just something for governments to deal with. People all over the world, Muslim and non-Muslim alike, are responsible too.