Michael Weiss is an international affairs analyst for CNN and author of "ISIS: Inside the Army of Terror." The views expressed are his own.

(CNN) Last month, the Pew Research Center released the results of a survey asking the citizens of 38 countries to name a major threat to their nation. This is the last in a special series of op-eds that also appear in Fareed's Global Briefing looking at the top perceived threats among Americans. You can sign up for the Global Briefing newsletter here .

A common misperception about ISIS-related terror is that the group's fortunes exist in inverse proportion to the square mileage of territory it controls. Carnage on the streets of London, Istanbul, Brussels, Paris and now Barcelona, according to this conventional wisdom, represents the death throes of a medieval enterprise which is crumbling in Syria and Iraq.

By taking out ISIS's administrative centers, revenue streams and willing executioners -- and therefore the symbolic strength represented by all of the above to galvanize new members abroad -- exportation of jihad will similarly wither away.

Yet such thinking ignores the long history of ISIS's foreign operations, which have outlasted the ups and downs in its real estate holdings and have long predated the establishment of the so-called "caliphate."

A decade ago, European security services uncovered and thwarted a number of Zarqawist plots to bring terror to the continent, even as the warriors of ISIS's predecessor network were escalating sectarian civil war in Iraq and nowhere near being strategically routed.

And well before ISIS lost the Kurdish city of Kobani, in a campaign that marked the initiation of the US.-led coalition's war in Syria and the beginning of its military downfall, the organization had been dispatching agents into Europe for the purpose of building up cells and minting a new rank-and-file of Western-born operatives who needn't have ever stepped foot outside their native countries.

This campaign, essentially ISIS's foreign policy doctrine, was built on the initial success of its jihadist nation-building. And it was wholly in keeping with the group's well-advertised total war against the West -- a war that was always meant to be fought not only in the deserts of the Middle East, but in the boulevards of Europe and the United States.

A defector from the Amn al-Dawla, ISIS's domestic spy service, told me in Istanbul two years ago -- weeks before the Paris attacks -- that he had personally trained two Arab-ancestry French foreign fighters who had subsequently been dispatched back to France. They had volunteered for this coalescing jihadist internationale and their new role was that of semiautonomous overseas assets who, for security reasons, were only be loosely answerable to ISIS HQ.

In fact, the true headquarters of ISIS's foreign operations planning, at least for attacks in Europe, was the Syrian city of al-Bab, in Aleppo province. The Turkish military, backed by Syrian rebels, retook it in February, a contingency that has not much disrupted the spate of knifings, bombings and vehicular homicides linked to known ISIS associations in Europe.

The now-dead ISIS spokesman Abu Mohammed al-Adnani, who was also the senior-most official in charge of Syria, issued his infamous injunction, instructing all true believing Muslims living the West -- sometimes known as the "gray zone" -- to murder American, European, Australian and Canadian innocents by any means necessary.

Yet while it's true that Adnani was looking to inspire those with no discernible connection to his organization, the "lone wolf" species of terror plot has actually seldom existed in Europe. What may first appear to be the work of a wannabe or fellow traveler individually radicalized by ISIS ideology, later turns out to have been more carefully orchestrated and staffed operation run by domestic networks that have existed for years.

This was certainly the case with the Christmas marketplace attack in Berlin last year, perpetrated by Anis Amri . It also increasingly seems to be the case with last week's Barcelona atrocity.

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Alexander Meleagrou-Hitchens, the research director at the Program on Extremism at George Washington University, and a specialist on Islamist terror in the West, told me that "only six out of 38 plots in Europe between 2014 and 2016 were truly planned and carried out by lone actors."

Even in the United States, he added, around one fifth of the 38 ISIS-inspired domestic plots and attacks between March 1, 2014, and March 1, 2017, involved some form of communication with what he calls "virtual entrepreneurs" -- online case officers employed by ISIS to instruct and provide logistical support for prospective attackers.

ISIS has also built up an array of offshore outposts, what it grandiosely calls wilayats, or provinces, to ensure its survival beyond the demise of its pseudo state. See Afghanistan, Libya, Russia, Yemen, the Sinai Peninsula, Indonesia and the Philippines. This means that despite the Pentagon's cheerleading, even the fall of Raqqa -- the group's so-called capital -- won't mark the end of the ISIS threat to Europe or the United States.