Two days after the terrorist attacks in London, British Prime Minister Tony Blair pointed to what he called terrorism's root causes: poverty, lack of democracy and the Middle East conflict. Blair said, "Where there is extremism, fanaticism or acute and appalling forms of poverty in one continent, the consequences no longer stay fixed in that continent, they spread to the rest of the world."

All of which may be true. President Bush and Secretary of State Condoleezza Rice have said pretty much the same thing. What any of that means as far as the London explosions are concerned is, however, another question.

Blair now knows, but apparently didn't suspect when he spoke last week, that three of the four alleged bombers were born and raised in an economically thriving democracy called Great Britain. The three men of Pakistani descent did not, by all accounts, lead lives steeped in economic desperation. The fourth bomber also did not hail from the turbulent Middle East. He was, according to U.S. law enforcement officials, a Jamaica-born British citizen.

They were, however, Muslims. And the four men were so disaffected from their own country that they acquired explosives, blew themselves up and, in the process, killed at least 50 strangers while injuring 700 more.

The presence of suicide bombers in London on July 7 had nothing to do with porous borders, an influx of counterfeit asylum seekers or weaknesses in British deportation laws. The men on those three subway trains and double-decker bus had one thing in common besides their faith and their British citizenship: a rage within that caused them to turn themselves into human bombs.

That put them in league with suicide terrorists from Iraq to Israel. So what is the West, including the United States, really up against?

Poor economic conditions in Arab countries, as the Bush administration asserts endlessly, may be an incentive for terrorism. But what accounts for those home-grown supporters of terrorism in the United Kingdom? How do you explain Ali Al-Timimi, the Muslim spiritual leader across the Potomac River in Fairfax County who was sentenced this week to life in prison for inciting his followers to train for armed jihad against America?

Timimi, reports The Post, was born and raised in the Washington area. The place where he lectured -- Falls Church -- is hardly an economic backwater, nor is it known as a hotbed of anti-American radicalism.

Now, you may argue with the length of Timimi's sentence. You may even believe his conviction for urging a jihad that never happened goes too far. But Timimi doesn't command my attention. I want to know what motivated his followers in Virginia and the four dead bombers in England. Notwithstanding their access to higher living standards and modern education, the British bombers and some of Timimi's followers found violent jihad an attraction. Some of the men who attended a Sept. 16, 2001, meeting in Fairfax -- at which Timimi was reported to have told that "the time had come for them to go abroad and join the mujaheddin engaged in violent jihad in Afghanistan" -- actually left the United States for terrorist training camps. Ponder that.

This takes me back to a 2003 column in which I interviewed Jessica Stern, then a lecturer at Harvard's Kennedy School of Government and author of "Terror in the Name of God: Why Religious Militants Kill."

Stern didn't think the Bush administration had a clear understanding of the religious extremists we are facing. Poverty in and of itself doesn't cause terrorism, she pointed out. To be sure, terrorist leaders recruit among the disenfranchised and target orphanages -- such as those in Pakistan -- as feeder schools for jihadist organizations.

The ranks of terrorist groups, however, also include young men and women from the middle class. The feelings they seem to share across the board, she said, had to do with humiliation, a desire for a clear identity, and a belief that they can control more through their deaths than through their lives. They have come to see murder-suicide and martyrdom as just rewards for avenging the harm done to their religion and to Muslims in other countries.

A misuse of Islam by terrorist leaders, to be sure. Murderers in the name of an extremist ideology? Yes. But -- and here's the lesson London learned that America cannot ignore -- alienation, blind hatred and fanaticism are not foreign imports. They can be homegrown. And just like firecrackers, they can explode.