THIS is a devastating assault on India, its democracy, its way of life and its brilliant economy, all of which excite envy and hatred from Islamic extremists.
But it is also a message from Terror Central to US president-elect Barack Obama.
Despite everything you Americans have done, the terrorists are saying, we can still hit you. We can hit your friends in their economic heartlands, and we can hunt down your citizens in the commercial capitals of your friends.
Only last week, al-Qa'ida ideological boss Ayman al-Zawahiri issued a statement exhorting jihadists everywhere to continue hunting Americans and British.
These attacks, in which US and British passport-holders were singled out for individual murder - as well, apparently, as Jews - have the al-Qa'ida imprint.
They demonstrate once more the savage, sectarian nihilism of the terror movements. It will nonetheless take some time for the identity and the origins of the perpetrators of this terrorist atrocity to become clear.
But high-placed Indian sources told me last night they were certain of cross-border Pakistani involvement. They do not accuse the Pakistani military, but the failed-state-like dysfunctional tribal areas of northern Pakistan have become the new training grounds and operational headquarters of global terror.
The deeper the Pakistani fingerprints on this, the greater will be the Indian demand for retaliation. These attacks will have dangerous consequences for intercommunal relations within India, especially Muslim-Hindu relations. Part of the purpose of the attack may also have been to try to drive the country away from Washington.
Ultimately this will be unsuccessful, but the Indian Left will argue that this trouble comes to the nation in part because of its friendship with the US, evident in the recent US-India nuclear deal.
The most important ally the US has acquired over the whole of the war on terror has been India.
For example, New Delhi's aid program in Afghanistan is by far the most effective per dollar. This has led to great hostility to India from the Taliban-al-Qa'ida network that ranges across the tribal areas of Pakistan and through large parts of Afghanistan. The two most active terror groups within India, the Pakistan based Lashkar-e-Toiba and the Indian-based Indian Mujahideen, have close contacts with al-Qa'ida.
There is also certainly an agenda to disrupt warming Pakistan-India ties.
Pakistan's civilian Prime Minister, Asif Ali Zardari, has recently made peace overtures to India, declaring Pakistan would drop its first-nuclear-strike doctrine and re-energise its efforts to bring terrorist bases in tribal areas of Pakistan under control.
When civilian Pakistani prime ministers make peace with India they enrage two groups - Pakistan's military establishment and its country's Muslim extremists.
This assault was exceptionally well-organised and co-ordinated, suggesting a substantial degree of training for its participants, and elaborate planning. It may be that we are looking at a template for future terrorist attacks.
In the past year or two, Southeast Asian intelligence agencies have been warning that Jemaah Islamiah terrorists have been considering moving away from bombs to shooting people, as a way of sowing maximum terror.
Bomb-makers are often detected merely by the purchase of bomb ingredients. Accumulating rifles is much easier.
And these attacks held Mumbai in terror for the better part of 24 hours. Although the cost in terms of terrorist lives is high, it gives the perpetrators a big return on their effort.
During the US presidential campaign, Joe Biden said that the US's enemies would challenge Obama in the first months of his presidency. Biden's prediction has come true sooner than even he expected.