We and the other Arab countries are doing very well against the Jihadist or ISL.  War causes more economic growth as we have seen from other wars but war cost money that could be used for many other projects that benefit society.  There will probably never be complete peace in the mid east as it is age old conflict of tribes vs tribes.   The lowering of oil prices has actually helped in bring down ISL as they do not have $100.00 per barrel oil to help fund their efforts. There is always a price to be paid for conflict, higher taxes to pay for it and the waste of human resources, it is never free. Sending off young people to fight should never be taken lightly, Vietnam and Iraq proved that.