There are more than 15 various extremist groups based in Damascus, ranging from the small, secular Palestinian-backed PFLP to both Sunni and Shiite Islamic fundamentalist groups.
There's Hezbollah, the largest and best-armed militia in the world. It's financed by Iran and supported and used by Syria as a proxy army inside Lebanon. Since last year's war with Israel, it's also been hailed as a legitimate resistance movement in the Arab and Muslim world.
The largest group based in Syria is Hamas, whose Islamist Green Revolution swept to power in Palestinian elections last year and then seized control of the Gaza Strip after ousting the Fatah forces in violent street battles.
"Why do you think the Syrian government has offered such strong and public support of Hamas?" Couric asks.
"We're facing the same problem, the same enemy," Marzouk says.
"Israel?" asks Couric.
"Yes, of course, Israel
Marzouk now operates from Damascus, where he directs much of the group's activities inside the Palestinian territories.
For people like Marzouk, Damascus is a safe haven where extremist leaders are granted diplomatic immunity along with channels for arms smuggling, banking and logistical support. It's a place where the three allies in the struggle against Israel and America are everywhere on display.
But most threatening of all to the U.S. are the hundreds of al Qaeda foreign fighters recruited throughout the Arab world who travel to Damascus, where they are met and escorted across the Iraq border to become human bombs.
"Syria has played a decisive role in frustrating the American project in Iraq in helping the resistance and the insurgency in Iraq, in bleeding forces in Iraq," says Sarah Lawrence College professor Fawaz Gerges.
Charged with fueling extremist fires to the east in Iraq, to the west in Lebanon, and to the south in Israel, President Assad has become one of the region's greatest jugglers. But it is a game that has left him increasingly isolated and dependent on Iran - his one strategic ally in the region.