TEL AVIV, Israel — Just as dozens of nations have entered into direct or de facto coalitions to fight external, military threats posed by the Islamic State group, so too should world leaders unite in a "coalition of principles" to combat internal threats generated by the group's s radical ideology, a top Israeli intelligence official told Defense News.

Chagai Tzuriel, director-general of Israel's Ministry of Intelligence, warned that even as ISIS is being ousted from territory gained in its campaign for a cross-border caliphate, its extreme, violent ideology could morph into new physical threats if nations are not focused on the so-called "day after."

"You first need to distinguish between the organization of Daesh and the phenomenon of Daesh," Tzuriel said, using the Arabic acronym for the Islamic State group. "Even if, or when, the organization is destroyed, the phenomenon is not going away. That's clear to everybody.

"And even if the organization is destroyed, some other wild growth can come out from there … which will all flow back to the basic phenomena to begin with."

According to Tzuriel, a 27-year veteran of Israel's Mossad, a coalition of principles to guide nations in their respective policies regarding internal security, online incitement, border security and more could serve as a bulwark for preventing the spread of destabilizing radicalization at home and abroad.

"Alongside military coalitions that have already been created, now we need a coalition of principles … in which like-minded countries could come together for purposes of dealing with Islamic extremism, radicalization and terror," Tzuriel said.

"Of course, each country would adjust these principles to its special circumstances, but the fact that they would exist could serve as a tailwind for leaders to push forward the changes necessary to deal with this threat," he added.

Tzuriel insisted that his self-described coalition of principles would be mindful of the fine balance to which countries — especially Western, democratic countries — must aspire with regard to security and personal liberties. Nevertheless, he said when terror threats abroad start to morph, mutate and take root at home, leaders could draw on such "principles" to justify security-oriented actions.

Tzuriel's boss, Intelligence and Transportation Minister Yisrael Katz, will be in New York and Washington over the next several days speaking with U.S. and international leaders about a broad spectrum of intelligence issues, including the war against ISIS and what Israel considers an ever-expanding threat from Iran.

According to Tzuriel, the greatest security challenge for Israel and the world — even beyond ISIS — is the specter of an Iranian Shiite crescent extending from its Hamas and Islamic jihadi clients in Gaza, on the Mediterranean Sea, all the way around and down to the Red Sea and the strategic Bab el-Mandeb strait, where Houthi rebels are battling a Saudi-led, U.S.-backed coalition in Yemen. Iran has been accused of backing the Houthis, but the country has denied its support for the militants.

Once ISIS is driven from the Iraqi city of Mosul and there is no other alternative power to take control there, Tzuriel said Iran will be able to complete its overland bridge, anchoring its power throughout the region. "If, after the fall of Mosul, Iran is able to create an overland bridge, we'll see the Shiite crescent with one side in the waters of the eastern Mediterranean and the other in the Red Sea and beyond," he said.

From Gaza, Tzuriel charts the crescent rising through Lebanon — where Iran-influenced Hezbollah continues to build up its military might — through Syria. It continues across Syria, where, with Russian help, Iran is building critical infrastructure and a long-term presence, including a seaport in the war-torn country. The crescent further extends through the Arabian Gulf, where Iran is engaged in "subversive activities" in Bahrain, around the Arabian Sea and down to the Gulf of Aden off the coast of Yemen before curving up again around the Red Sea.

"The Iranians are dipping their feet in the East Med, planting them across Lebanon, Syria and Iraq and then using them to churn up all sorts of instability in the Straits of Hormuz and on to the Red Sea," Tzuriel said.

"We're not the only ones saying that Iranian hegemony, if left unchecked, will forever sentence this region and beyond to a reality of instability and strife."

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