In recent days, U.S. and Mideast officials have reported that Iran and Hezbollah, the Lebanese Shiite group, are making military preparations for the sectarian chaos likely to engulf a post-Assad Syria. Counterterrorism expert Matthew Levitt says that Hezbollah has closely aligned itself with Iran's Quds Force, an elite paramilitary group linked directly to Ayatollah Ali Khamenei, while fighting alongside the Assad regime. In recent years, the partnership between Hezbollah and Iran has tightened to the point that the group's allegiance to Khamenei is paramount, he says. "What we see now is that Hezbollah is going to do things today that are in Iran's interest even if they expressly run counter to the interests of Lebanon and Hezbollah's own interest there."

Israeli warplanes recently bombed a truck convoy in Syria, reportedly carrying antiaircraft missiles to Hezbollah in Lebanon. Why would Syria be shipping weapons to Lebanon instead of the other way around?

Hezbollah has long stockpiled weapons in Syria, and the Assad government has long provided some of these weapons to Hezbollah. In addition, Iran has often supplied weapons to Hezbollah through Syria. As events in Syria turn worse for the Bashar al-Assad regime, Hezbollah is going to--as we've already seen--try to move as much of its weapons to safer ground. Some of its stockpiles [are] in Lebanon where it has dug caves into mountains.

Both sides of this conflict, the more radical Sunni extremists embedded with the rebels and the Shiite extremists aligned with Hezbollah and Iran, are setting up militias who will be loyal to them after the fall of the Assad regime. What we're seeing is the stockpiling of weapons for that second phase of conflict.

So you think Hezbollah now has come to the conclusion that Assad is not long for the world?

They came to that conclusion a little while ago. They want to set things up so they are positioned to continue to have influence in Syria even after Assad is gone and a Sunni majority remains.

How has Hezbollah been helping out Syria in this civil war?

There's tremendous amount of evidence that Hezbollah has been aiding the regime, especially with training. There are also reports of snipers trying to hold key pieces of territory, especially along the border with Lebanon.

Hezbollah was designated as a terrorist group by the U.S. government in 1997; it's on the State Department's list of Foreign Terrorist Organizations and on the Treasury Department's list of global terrorist entities. It was re-listed by Treasury just a couple of months ago for its support of the Assad regime and for its undermining security and stability in Syria. When the State Department released that designation, it included --as State and Treasury always do in these press statements--a little bit of declassified intelligence. One of the snippets that almost nobody's picked up on was that the individual responsible for overseeing Hezbollah's activities in Syria is Hassan Nasrallah himself, the group's long-time leader.

Is Hezbollah still a jihadist group?

It still is, but Hezbollah is multiple things: Hezbollah is one of the dominant political parties in Lebanon, as well as a social and religious movement, catering first and foremost to Lebanon's Shiite community. The group is also Lebanon's largest militia. After the 1989 Taif Accords, which ended Lebanon's civil war, the group was rebranded as a kind of an Islamic resistance.

People tend to misunderstand the relationship between Hezbollah and Iran, which has changed over time but is now extremely close. The U.S. intelligence community has publicly described this as a "strategic partnership." But people don't fully appreciate Hezbollah's ideological commitment to the concept of "velayat-e faqih," or guardianship of the jurists, which holds that a Shiite Islamic cleric should also serve as supreme head of government. For Hezbollah, this means the Iranian leadership is also their leader--not for every foot soldier, but for Hezbollah's senior leaders absolutely.

So what we see now is that Hezbollah is going to do things today that are in Iran's interest even if they expressly run counter to the interests of Lebanon and Hezbollah's own interest there. At the end of the day, the group's commitment to Iran trumps its identity as a Lebanese political movement. Part of that has to do with the assassination of Imad Mughniyeh in 2008, who led Hezbollah's military wing.

What was the fallout there?

Mughniyeh led Hezbollah and is believed to have had close ties with the Iranian Quds force. Because of that, Iran had tremendous faith in him. If he was told to do something by Iran, he could hold them off a little bit. But his successors, his cousin Mustafa Badre al-Dine in particular, are nowhere near Mughniyeh in stature, so Iran doesn't have the same trust in him. Therefore, the strategic partnership has become even closer.

If you look at Hezbollah's attacks against Israeli tourists worldwide, there's no way they can be described as in Lebanon's interests in any way. Look back at Hezbollah's support of Shiite militants in Iraq during the Iraq war; look now today to Hezbollah helping to ferry Iranian weapons to houthi rebels in Yemen; look just recently to Hezbollah's flying a dronenear the Israeli nuclear reactor in Dimona. None of this is in Lebanon's interest.

And this bombing in Bulgaria?

The Bulgarians recently concluded that Hezbollah operatives carried out the July 2012 bus bombing in Burgas. A week before the Burgas bombing, an individual Hezbollah operative with dual Lebanese-Swedish citizenship was arrested in Cyprus for carrying out surveillance on Israeli flights and tourists. Six months earlier, [there was] another Hezbollah plot targeting an Israeli tour bus on its way to Bulgaria for a skiing trip --an attack that was thwarted.

So the Bulgarian investigation is only the first shoe to drop in Europe. There's a tremendous amount of activity going on and none of it can be described as being in Lebanon's interests, or in the interest of Hezbollah's political aspirations in Lebanon.

What's going on in Lebanon? Is Beirut a thriving city now? How evident is Hezbollah's presence?

Beirut isn't a thriving city; it's a divided city. The signs of Hezbollah are all over the place, especially where the group is dominant, like south of the airport. There's a lot of tension because Hezbollah has recently been accused of doing things that are not in Lebanon's interest. Just last week, a Hezbollah member was arrested for the July 2012 attempted assassination of Bourus Harb, a member of parliament; and the group has also been implicated in the killing of Wissam al-Hassan a few months later. Moreover, Hezbollah operatives, including Mustafa Badre al-Dine, stand accused by the UN Special Tribunal for Lebanon at The Hague of assassinating former prime minister Rafik Hariri, who was the de facto leader of the Sunni community.

Does the United States have any role to play in combating Hezbollah?

Without question the U.S. has a role to play, especially when it has partners that are willing to work with it. That means pressing the Europeans to take Hezbollah more seriously. The European Union designation of Hezbollah as a terrorist group would be a shot across the bow, telling the group that it needs to make a choice to be either political or militant. It would also empower European countries to do more to prevent the travel of Hezbollah operatives to Europe, which Hezbollah treats as its near abroad, and to raise funds there, which Hezbollah does today hand over fist.

White House counterterrorism adviser John Brennan made an excellent point speaking in Ireland last October, where he said one of the reasons Washington wants the Europeans to designate Hezbollah as a terrorist group is that some European countries cannot or will not open counterterrorism investigations into the group until this distinction is made.

But it's not just an American or European effort: the Yemenis right now are tremendously concerned about recent arms shipments from Iran that they have seized destined for houthi rebels. The Yemenis have said there's evidence that Hezbollah is involved. And we see Hezbollah's activities elsewhere as well. Some of the Shiite militant groups that Hezbollah trained to fight coalition forces in Iraq have now turned up in Syria, fighting alongside Hezbollah and supporting the Assad regime. So, there's a lot that can be done to a) counter Hezbollah's actual terrorist operations, and b) frustrate the group's ability to procure weapons and fundraise worldwide.