Of course we'll survive,the question is will things be like they were before?
No, they won't. How good or bad it will be is up to us.
We need good leadership, we need to strengthen the foundations of our economy by becoming more self sufficient in energy, capital, manufacturing, and so on. We need monetary reform, specifically a free market for money and credit, so we don't need continuous debt inflation to keep our heads above water, we need fiscal discipline,deficit spending is the same as taxation, worse even, the people still pay the bills through inflation and then again when the debt comes due, we need to start building an infrastructure that better serves the needs of people with fewer oil and other inputs, and we need to manage all that on a budget that represents a smaller percentage of our GDP.
Otherwise things could get pretty bad, but we'll survive. We may not recognize ourselves but we'll still be here. It'd take a major power with a death wish to take us down with them.
By the way, 9/11 had little to do with the economic weakness of the last few years, it had more to do with fundamentals, debt burdens, overcapacity, and trade imbalances. Things would have been worse without the massive liquidity injections from rate cuts and so on, which were temporary fixes which have only made the problems worse. Whenever human beings try to manage an economy they can only trade one problem for another, at best. Since they're not omniscient they end up doing damage every time they intervene.
THAT's the threat, not storms or guys with boxcutters, they're just the shit that happens.