The next target will be one we haven't thought of. A suicide bomber wearing the explosives would do relatively little damage (compared to 9/11) it would make Al Qaeda look weak and unable to mount anything significant. The Super Bowl would not make a good target because except by air, no one will get close enough with enough explosives to do any significant damage. There is always that chance we have simply made ourselves too difficult a target for Al Qaeda and they are focusing on softer targets.
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Ever heard of this little scrimmage they call The Rose Bowl?