International terrorism has become largely a matter of Arab expatriates living in Europe, or Arabs in Middle Eastern countries, making their way to Iraq, and getting killed, or disillusioned and going home, after a brief fling with danger and violence. What has been most frightening is the inability to find any of these young, European born Arabs, who have gone to Iraq and come back. It appears to be a one way trip. The few that have come back appear to be disillusioned. But it's the ones who came back quietly, and are still eager to wage a terrorism war in Europe, that is most worrisome. What appears to be happening is the same thing that occurred during the 1980s in Afghanistan. Thousands of Arab volunteers went to Pakistan, to try and help out Afghan "Holy Warriors" that were operating out of Pakistani refugee camps, and going into Afghanistan to fight Russians. Few Arabs crossed the border into Afghanistan, because the Afghans did not want to risk their lives with a bunch of amateurs. Few Arabs had any combat experience, and Arabs in general had a poor fighting reputation among Afghans. The Arab volunteers would hang out in the refugee camps, help out if they could, get their picture taken carrying an AK-47, drink a lot of coffee, tell a lot of stories, and eventually go home a hero.
It was much easier to get into Afghan refugee camps in the 1980s, than Iraqi terrorist safe houses since 2003. Syria and Iran have been hospitable, although covertly, to terrorist wannabes flying in with the intention of getting across the border. While there is some government assistance from Syria and Iran, most of the recruiting and travel arrangements are handled by Baath Party and al Qaeda personnel in Syria, and Shia Islamic radicals in Iran. Syria is the main conduit of volunteers, because Iran is rather hostile to al Qaeda (which is basically anti-Shia, and responsible for recent murderous attacks against Shias.)
Turkey, Jordan, Kuwait and Saudi Arabia are all very anti-terrorist, and make it difficult, but not impossible, for foreign tourists to get across the border into Iraq. Getting illegal visitors into Iraq has now become a big business, with smugglers and other criminal gangs charging large fees to slip the terrorist hopefuls into Iraq. It's a dangerous business, as American and Iraqi border patrols will shoot to kill if they find suspicious people in out of the way places. Apparently thousands of eager young Arab men have been arrested while headed for the border, and deported, or killed after crossing the border, and running into American and Iraqi troops.
European counter-terrorism organizations believe that only a few hundred of their citizens have tried to make the trip to Iraq, and most have disappeared. The number of Middle Eastern Arabs who have tried appears to be in the thousands. More of these have returned, often with horrific stories of fighting American and Iraqi forces, and getting the worst of it. But a larger number of the Middle Eastern volunteers have not come back, and many have been confirmed dead.
Trying to track down survivors of the al Qaeda effort in Iraq is a top priority by counter-terrorism efforts everywhere. Any terrorist who comes out of Iraq in one piece will not only be experienced in many terrorist techniques, but also a very tough, capable, and lucky operator. A few of these fellows could be extremely dangerous.