For liberal critics, as well as some Republicans, President Trump’s temporary travel ban couldn’t have been a better gift to Islamic State militants, the same terror group that Mr. Trump has pledged to crush. Some arguments say the ban, which blocked US admittance of travelers from seven majority-Muslim countries for 90 days, could give the appearance that the West agrees that it is indeed at war with Islam – IS's worldview – thereby buoying recruitment and funding for a group whose star was fading.
But in the immediate wake of the executive order, that argument was more speculative than concrete, based on assumptions derived from what experts have said about how Islamist terror groups attract new members, rather than in how IS actually responded to the news.
Some evidence has since emerged: IS-friendly chatrooms, where sentiment tends to reflect that of the group’s rank and file, have pointed to the order as evidence of a “clash of civilizations,” terrorism expert Mia Bloom told Business Insider last week. And New York Times terrorism correspondent Rukmini Callimachi, reporting from Mosul, tweeted that one resident of an IS-controlled part of the city said that IS members had been “openly celebrating” the ban, dubbing it the “Blessed Ban” – an echo of Al Qaeda’s term for the “blessed invasion” of Iraq in 2003.
But IS propaganda outlets have remained silent about the ban, a silence that appears to hint at less-than-obvious strategizing from the group’s leadership and underscoring the complex sources of the group’s appeal.
"By now we have seen ISIS members and supporters jumping up & down with glee at ban,” wrote Ms. Callimachi in a tweet on Wednesday.
"Yet we still have not seen an *official* ISIS statement regarding the ban and Trump. By contrast, al-Qaeda has put out several," she went on.
"I have to say I don't get that. Why is ISIS in its official pronouncements being silent on Trump & on the ban?"
The visa ban adds an element of uncertainty to the campaign against IS, banning citizens from Iraq – a close military ally and one of the campaign’s leaders – at a time when the US-backed coalition has expressed confidence that it could drive the group from remaining strongholds over the next several months. But it’s unclear whether it could conjure a waning aura of excitement surrounding IS, a factor some experts say has been overlooked in dissections of its appeal.
"It is phenomenally exciting for them to be part of this, this secret club,” said John Horgan, of the University of Massachusetts' Center for Terrorism and Security Studies, in a 2015 interview with the Associated Press. "And once that takes root ... that excitement completely outweighs anything we can do to try to counter it."
Elsewhere, the ban's galvanizing of other hardline, fundamentalist opponents of the United States has been clearer. In Iran, Supreme Ayatollah Ali Khamenei heralded it as the “true face of America.”
The effect, analysts say, may be the opposite of what’s intended: spurring average Iranians to rally around a ruling system whose hard lines they often chafe against. The Christian Science Monitor’s Scott Peterson reported this week:
“If Trump intended to damage Iran, he missed it, as the nation now is gathering behind the nezam [governing system] and supporting it,” says an Iranian official in Tehran who asked not to be named.
“As long as [US] policies target the nezam, people would say that it is the system which wants to be the black sheep and does not abide by international norms,” says the official. “But now it is different…. Trump is putting back in place the small parts of that wall of distrust that were [pulled down] by the nuclear deal.”
For terror groups, though, officials of enemy states can embolden them, "but not always in as visible or simple a way as is often implied," said Charlie Winter, a senior research fellow at the International Centre for the Study of Radicalisation and Political Violence, in an interview with Politfact.
"I am in no doubt that Trump's executive order will make the lives of ISIS and its like-minded rivals easier, but I would be wary of drawing too linear a link."