In an extraordinary intelligence coup, the double agent left Yemen, traveling by way of the United Arab Emirates, and delivered both the innovative bomb designed for his air attack and critical information on the group’s leaders to the C.I.A., Saudi and other foreign intelligence agencies.

After spending weeks at the center of Al Qaeda in the Arabian Peninsula, the agent provided critical information that permitted the C.I.A. to direct the drone strike in early May that killed Fahd Mohammed Ahmed al-Quso, a senior Qaeda militant in Yemen linked to the bombing of the Navy destroyer Cole in 2000 that killed 17 sailors. The double agent also handed over the bomb, designed by the group’s top explosives expert to be invisible to airport security, to the F.B.I., which is analyzing its properties.

Officials said the agent, whose identity was not disclosed, works for the Saudi intelligence service, which has cooperated closely with the C.I.A. for several years against the terrorist group in Yemen. He operated in Yemen with the full knowledge of the C.I.A., but not under its direct supervision, the officials said. The agent is now safe in Saudi Arabia, officials said. The bombing plot was kept secret for weeks by the C.I.A. and other agencies because they feared retaliation against the agent and his family.

The Arab Spring

The Arab Spring began to unravel an alliance of so-called moderate Arab states, led by Saudi Arabia and Egypt, which were willing to work closely with the United States and promote peace with Israel. American support for the Arab uprisings also strained relations, prompting Saudi Arabia to split from Washington on some issues while questioning its longstanding reliance on the United States to protect its interests. Washington has also indicated that the glacial pace of reforms Saudi Arabia has been engaged in since 2003 must accelerate.

Saudi officials were deeply displeased with President Obama‘s handling of the ouster of the Egyptian president, Hosni Mubarak, charging Washington with abandoning a longtime ally. King Abdullah told Mr. Obama that the United States should support Mr. Mubarak, even if he began shooting protesters. That advice was ignored. “They’ve taken it personally,” said one senior American familiar with the conversations, “because they question what we’d do if they are next.”

Any suggestions that Riyadh was ready to go it alone seem at least partly a display of Saudi pique, since the oil-for-protection exchange that has defined relations between the two for the past six decades is unlikely to be replaced soon. Saudi Arabia is negotiating to buy $60 billion in advanced American weapons, and President Obama, in his speech in late May demanding that Middle Eastern autocrats bow to popular demands for democracy, noticeably did not mention Saudi Arabia.

Saudi Arabia is taking each uprising in turn, without relying on a single blueprint. In Bahrain, it resorted to force, sending troops to crush a rebellion by Shiites because it feared the creation of a kind of Shiite Cuba only about 20 miles from some of its main oil fields, one sympathetic to, if not allied with, Iran. It has deployed diplomacy in other uprisings — and remained on the fence in still others. It is also spending money, pledging $20 billion to help stabilize Bahrain and Oman, which has also faced protests.

At Home, Muted Dissent

Domestically, the Saudi effort to defuse serious protests appears to take a different approach: a huge police presence, which smothered relatively small demonstrations; an appeal to the innate religious conservatism of the country; and $36 billion in pay raises, housing support, unemployment benefits and other promised subsidies in a country that is already the ultimate welfare state.

The monarchy has not completely escaped calls for change. There have been at least three petitions, with a group of youths and even some members of the Sahwa, the staunchly conservative religious movement, calling for an elected consultative council.

The only major street protest scheduled for March 11 largely fizzled — its organizers were anonymous, and its stated goal of toppling the government lacked broad appeal. In the largely Shiite eastern provinces, though, police officers arrested scores of protesters.

The ruling princes have also moved against dissent in other ways, like imposing a new press law with punishments including a roughly $140,000 fine for vaguely defined crimes like threatening national security.

Saudis of all stripes say that they are less concerned about democratic elections than about fixing chronic problems, including the lack of housing, unemployment that is officially 10 percent but likely 20 percent or more, corruption, bureaucratic incompetence and transparency on oil revenues.

Saudi women, who are legally subject to male chaperones for almost any public activity, hailed King Abdullah’s September decree as an important, if limited, step toward making them equal to their male counterparts. They said the uprisings that have swept the Arab world — along with sustained domestic pressure for women’s rights and a more representative form of government — prompted the change.

Although political activists celebrated the change, they also cautioned how deep it would go and how fast, given that the king referred to the next election cycle, which would not be until 2015. Some women wondered aloud how they would be able to campaign for office when they were not even allowed to drive. And there is a long history of royal decrees stalling, as weak enactment collides with the bulwark of traditions ordained by the Wahhabi sect of Islam and its fierce resistance to change.

In his announcement, the king said that women would also be appointed to the Majlis Al-Shura, a consultative council that advises the monarchy on matters of public policy. But it is a toothless body that avoids matters of royal prerogative, like where the nation’s oil revenue goes.

Dual Saudi Strategies

Amid the region’s turmoil, Saudi Arabia’s proposal to include Jordan and Morocco in the six-member Gulf Cooperation Council — which authorized the Saudis to send in troops to quell a largely Shiite Muslim rebellion in the Sunni Muslim monarchy of Bahrain — is intended to create a kind of “Club of Kings.” The idea is to signal Shiite Iran that the Sunni Arab monarchs will defend their interests, analysts said.

The range of the Saudi intervention has been extraordinary, as the unrest pushes Riyadh’s hand to forge what some commentators, in Egypt and elsewhere, brand a “counterrevolution.” Some Saudi and foreign analysts find the term too sweeping for the steps the Saudis have actually taken, though it appears unparalleled in the region and beyond as the kingdom reaches out to ally with non-Arab Muslim states as well.

In Egypt, where the revolution has already toppled a close Saudi ally in Hosni Mubarak, the Saudis are dispensing aid and mending ties in part to help head off a good showing by the Muslim Brotherhood in the upcoming parliamentary elections. The Saudis worry that an empowered Muslim Brotherhood could damage Saudi legitimacy by presenting a model of Islamic law different from the Wahhabi tradition of an absolute monarch.

In Yemen, Saudi Arabia joined the coalition seeking to ease out President Ali Abdullah Saleh because it thinks the opposition might prove a more reliable, less unruly southern neighbor. But Arab diplomats noted that even the smallest Saudi gestures provided Mr. Saleh with excuses to stay, since he interpreted them as support.

On Syria, an initial statement of support by King Abdullah for President Bashar al-Assad has been followed by silence, along with occasional calls at Friday Prayer for God to support the protesters. That silence reflects a deep ambivalence, analysts said. The ruling Saudi family personally dislikes Mr. Assad — resenting his close ties with Iran and seeing Syria’s hand in the assassination of a former Lebanese prime minister, Rafik Hariri, a Saudi ally. But they fear his overthrow will unleash sectarian violence without guaranteeing that Iranian influence will be diminished.

In Libya, after helping push through an Arab League request for international intervention, Saudi Arabia sat out and left its neighbors, Qatar and the United Arab Emirates, to join the military coalition supporting the rebels. It has so far kept its distance publicly from Tunisia as well, although it gave refuge to its ousted president, Zine el-Abidine Ben Ali.

There are also suspicions that the kingdom is secretly providing money to extremist groups to hold back changes. Saudi officials deny that, although they concede private money may flow.

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