The economic consequences of terrorism are incalculable, ranging from the immediate havoc wrought by the terrorists to a long-term miasma of gloom and uncertainty. It is sometimes said that the two bombs the IRA let off in the City of London inflicted more damage to Britain than all the rest of its campaign because they scared off American bankers. Yet the tragically more deadly bombings in July last year did not.
Wall Street, New York and the American economy recovered heroically from the attacks of September 11, 2001 - with the help of ultra-low interest rates. But if you link t hose events with the Bush/Blair war in Iraq and its aftermath and then with the subsequent oil price explosion, the damage is deeper, more insidious.
But you could be wrong. On the face of it, the present oil price shock has more to do with demand from China than fears about Middle Easterners cutting off supplies.
The stock market's response to yesterday's episode of (hopefully) thwarted terrorism was reassuring. An instinctive 100-point mark-down on the Footsie first thing was steadily eroded as the day wore on - with the implication that provided nothing worse happens, it should be business as usual.
BA and other airlines have taken a knock - but so they did from the summer strikes of 2003 and 2005. The recent re-surgence of tourism from America may dry up now. But with the pound approaching $2 it was never likely to amount to much. As it happens, sterling did slip nearly two cents against the green-back yesterday, a small mercy, but welcome nonetheless.
What we have had, though, is a chilling reminder that terrorism has become a fact of life. It is not always going to be thwarted.
What is the difference between Gordon Brown and Denis Healey? It is still not quite certain that Gordon will succeed where Denis failed in becoming leader of the Labour Party. Denis generously volunteers that Gordon has been a far more successful.
Chancellor, albeit in far easier times. But the key distinction is that while Denis micro-managed the British economy, Gordon doesn't try. In the global economy it not on - and a good thing, too, in the view of Dennis Turner, chief economist at HSBC Bank.
Mr Turner's case is that a successful Chancellor is one who makes Britain a good place to do global business - a country that copes in a fast-changing global economy, with global-minded companies that know how to handle interest and currency risks (or else use the services of a global bank like HSBC, of course). Stability is critical. If interest rates go up to five per cent this winter it will be for the first time in five years, no less.
The other trick is to have just enough regulation - red tape in moderation actually attracts foreign companies seeking a stock market listing without the overkill the postEnron Sarbanes-Oxley law has imposed on America.
There is even a North Korean mining company heading for AIM this autumn. Fine by me - provided the investors are Russian.