I cannot imagine terrorists bring in that much money, and any they do is likely to be spent on their own activities.

I can think of only 1 country where terrorism is "allowed" just as long as they do not attack the host. Syria. Papa Assad waxed the village Hamas to the tune of 20,000 people because they had the temerity to hide behind the Islamic Brotherhood and oppose his secular regime. After the shelling stopped, he bulldozed it and then invited his people to see for themselves just what a man of the people he could be when threatened. After that, he more or less allowed the M.B.'s to set up shop on the fringes. They could do what they liked as long as they left Syria alone. After Iran fell, he allowed Hizbullah (sp?) the same privileges. Syria shares a long border with Iran and Assad wanted no interference from Iran.