For almost all of its existence, the Islamic State in Iraq and the Levant (ISIL) has focused on a spectacular yet singular goal: the creation of a new Islamic caliphate centered around Syria and Iraq. While there were threats and attacks further afield, these attacks were generally made by groups or individuals with relatively weak links to the group's core.

A week ago, ISIL militants in Libya released a video that showed the gruesome execution of 21 Egyptian Christians who had been kidnapped in December and January. It claimed to be the first propaganda video from the Libyan branch of the extremist group.

The response to the video has been dramatic, with Egypt bombing ISIL positions in Libya, retaliatory bombings by ISIL, and a remarkable escalation of concern about the terrorist group in Europe. It seemed like finally the extremist group was truly stepping outside of the caliphate.

Despite the shock of the video, however, it was really just proof of what we already knew: ISIL has had a presence in Libya for months. Last October, members of the Darna-based Islamist group Shura Council for Islamic Youth pledged fealty to Abu Bakr al-Baghdadi, ISIL's leader. Sources have said that this ISIL branch now has 800 fighters and that 300 Libyans who had traveled to Syria to fight for Baghdadi had now returned, bolstering these numbers.

What is the strategic value of Libya for ISIL? One worrying answer comes from an unofficial ISIL letter translated by London's Quillam Foundation. In that letter, written by a supporter who uses an alias, Libya was described as a "gateway" for the group, with a "strategic geographic" that "looks upon the sea, the desert, mountains, and six states: Egypt, Sudan, Chad, Niger, Algeria and Tunisia."

Europe, in particular, becomes a viable target for the group from Libya, which the author notes "can be reached with ease by even a rudimentary boat."

That talk of Libya's strategic location has Europeans concerned, nowhere more so than in Italy. The Italian island Lampedusa is just over 100 miles from Libya. The country's colonial past in Libya also adds a worrying historical dimension. Italy, clearly worried, called on the United Nations on Wednesday to confront the problem in Libya.

ISIL's interest in Libya may well be based on opportunism as well on strategy: Libya's ongoing chaos has provided a window of opportunity.

"Security in Libya has been deteriorating since 2012," said Christoper Chivvis, a senior political scientist at the Rand Corp., "but the situation grew especially bad over the summer, just as ISIL was making inroads in Iraq, so there is a confluence of events."

There's little central authority in Libya, and major cities like Darna have a long history of Islamist movements that date back deep into the Moammar Gadhafi era. These Islamist groups have taken over important parts of the country, and, at times, their actions don't look so different from ISIL: The Shura Council for Islamic Youth carried out a horrific public execution in a soccer stadium months before it pledged allegiance to Baghdadi.

The vast number of weapons in the country, a result of the recent civil war, are another major factor for ISIL.

In January, Aaron Zelin of the Washington Institute for Near East Policy wrote about ISIL's "model" for its franchises, pointing out that the group had announced several months ago that it was "annexing" territory in Algeria, Libya, Egypt's Sinai region, Saudi Arabia, and Yemen.

It's an ambitious plan, but at one point so was the caliphate in Syria and Iraq. Now ISIL is following the same model in Libya, said Cole Bunzel, an academic who studies the group. "Then, as now, the group announced its expansion to a new territory and gradually began winning recruits and taking territory." Can it succeed again?