Within hours of the attack on London, some of the Muslim world's most influential preachers were expressing their outrage.
Sheikh Mohammed Tantawi, who runs the venerable Al Azhar university in Cairo, told Islamonline.com, "Those responsible for the London attacks are criminals who do not represent Islam."
Yusuf al-Qaradawi, an influential Muslim scholar based in Qatar with a vast Internet and satellite television following, called the blasts "cruel and barbaric black actions that Islam harshly condemns."
But even a man like Mr. Qaradawi - a controversial figure who has some credibility with extremists for his past praise of suicide attacks against Israel - has little influence among the tiny sliver of Muslims who are now prosecuting what they see as a global jihad, analysts say.
While Islamic preachers speaking out against terrorism play a useful role in efforts to stem the spread of the global jihad, the rejectionist, or takfiri, beliefs of those already committed to extreme violence lead them to tune out any and all criticism of their methods.
Analysts say the men who attacked London, for instance, were probably influenced by extremist preachers like Abu Musab al-Suri, a Syrian exile who lived in London in the late 1990s. Mr. Suri is alleged by Spain to have aided in the Madrid train bombings on March 11, 2004. He's also sought by investigators in connection with the London attack and has carved out a place for himself as an uncompromising advocate of violent jihad.
Last January he released a book titled "Jihad," which Israeli terrorism expert Reuven Paz calls "the largest book ever written" in terms of breadth and length on the subject. Suri has criticized Osama bin Laden for failing to use nuclear or chemical weapons in the Sept. 11, 2001, attacks on the US, and dismisses all Islamic authorities who criticize the use of terror tactics as "infidels."
Almost as soon as the likes of Qaradawi and Tantawi condemned the London attacks, Internet message boards popular with many radical Muslims dismissed them as betrayers of Islam. One person posting a message on the Forum for Unity and Jihad dismissed Qaradawi as "an infidel ... who even defended the heretic Shiites and Christians."
Another anonymous poster attacked Saudi religious figures who condemned the bombings as "Sheikhs who work for an infidel regime that serves the Americans."
Reactions to the latest attacks conform to two trends - one positive, and one alarming - that analysts have followed for years. The first is the growing willingness of Muslim religious leaders to speak out strongly against acts of violence in the name of Islam and to attack the jihadis' justifications on theological grounds.
Alarming is the hardening of the positions of men like Suri or the Jordanian militant Abu Musab al-Zarqawi, leader of the radical faction of foreign fighters in Iraq, whose rhetoric and calls for blood exceed what came from Afghan-based groups of terrorists like Al Qaeda a few years ago.
"When the Arab Afghans got started, they were people from established groups like the Muslim Brotherhood, from radical factions of course, but they were still from the Brotherhood and maintained the rules on what was permissible that the Brotherhood had established,'' says Evan Kohlmann, a terrorism expert and author of "Al Qaeda's Jihad in Europe."
"Guys like Zarqawi are from a later generation of mid-level commanders [who] are extreme beyond all extremes ... and they've gradually taken over, both in North Africa, the Middle East and in Europe."
To be sure, wars of ideas are fought over decades, if not generations, and most Muslim leaders are increasingly laying the groundwork to further isolate and delegitimize Al Qaeda and its fellow travelers.
Last Wednesday - a day before the attack in London - a little noticed Islamic conference in Jordan brought together nearly 200 representatives of Islamic senior leaders like Iraq's Shiite Grand Ayatollah Ali al-Sistani, Egypt's Grand Mufti Ali Jumaa, and Qaradawi.
The scholars condemned the practice of branding other Muslims as "infidels" - the intellectual tactic that men like Mr. Zarqawi use to justify the killing of civilians - and also the frequent use of fatwa, or religious rulings, by friends of the jihadis who are seen as religiously unqualified. "No one may issue a fatwa without the requisite personal qualifications," they said in a statement after the meeting.
The prominence of lay preachers like Ayman al-Zawahiri, an Egyptian medical doctor and Al Qaeda's chief ideologue, has long been a source of frustration to Islam's mainstream scholars, or Ulama, who consider their interpretations of the Koran to be ignorant and misleading, particularly their willingness to kill noncombatants.
While the jihadis shoot back that the Ulama are coopted by "corrupt" regimes - Zarqawi has called Qaradawi a "sultan of the television" who has "abandoned the mujahideen" - the force with which men like Qaradawi are speaking out does yield benefits, say some analysts.
Even when Abu Muhamad al-Maqdsi, the cleric who served as Zarqawi's religious teacher when the two men were in prison together in Jordan in the 1990s, attacked Zarqawi's methods in Iraq - calling the number of civilian deaths in suicide bombs there a "tragedy" - Zarqawi turned on his old mentor. "Do not follow the path of Satan that leads to your destruction,'' he said.
"The hard core really are in a sense beyond reason - moderate scholars are not going to influence their views or behavior,'' says Marc Lynch, a professor of political science and a Middle East expert at Williams College in Massachusetts. "But if you're the kind of person who might become a jihadi, there's a chance you might take the moderates' criticisms seriously."
Mr. Lynch says the real importance of consistent attacks on the takfiri line is that it's probably convincing at least some fence-sitting young men to not go over to the other side. "What they can do is prevent the hard-core types from attracting a lot more recruits and supporters. If you didn't have the counterbalance of these denunciations, the momentum would be all on one side. It's not a silver bullet, but it might keep their growth at a standstill," he says.