Iraq and terrorism

The hardest example for terrorism in the last time was the terror attack on september 11,2001.There,two plains were flying directly into the twin towers.in this time they were lots of people in the towers and after half an hour both towers lost structural integrity and fell down killing almost 3,000 people within.
After this attack the USA was shocked and hopless.now the word terrorism has since this date a new meaning.the people all over the world pay more attention and you can really say they have panic.since this time george W. bush is fighting against terrorism all over the world.the opinions about this are very different because it costs lots of lifes.now what to do?Build a new world trade center?is it safer than the last?
an other question is:can you combat terrorism or is this the reason for the next terrorism?