As core al-Qaida weakened, its successors spread like weeds through Middle East, North Africa

During a search and destroy mission, U.S. Navy SEALs discover a large cache of munitions in one of more than 50 caves explored in the Zhawar Kili area. U.S. Navy photo / Wikimedia Commons.

WASHINGTON—Osama bin Laden is dead and al-Qaida dispersed, yet the horrors keep coming.

Western hostages beheaded on camera. School girls abducted by gunmen in the night. Families fleeing their homes in fear they might be executed because of their religion. The news from much of the Middle East and Africa is relentlessly brutal.

The Islamic State group’s rampage through Iraq and Syria has shocked the United States into launching expanded air strikes at a time when Americans were expecting to pull back from the Middle East after more than a decade of war.

Meanwhile, like-minded militants are gunning people down and blowing them up on a smaller scale in Afghanistan, Pakistan, Libya, Nigeria, Somalia and beyond.

While the 13-year U.S. campaign against al-Qaida tamped down its core leadership, the terror group’s followers, offshoots and wannabes have spread.

“They’re attracting more troops to these individual jihads than al-Qaida was ever able to attract in the past,” said Andrew Liepman, former deputy director of the National Counterterrorism Center. “The movement is still alive.”

A look at what happened:

Why now?

The number of extremist Sunni fighters more than doubled from 2010 to 2013, said Seth Jones, author of a RAND Corp. study released this summer that tracked seven years of increasing violence.

Among the reasons:

• Weakened governments left nations vulnerable: Iraq failed to build a strong, unified government after a U.S.-led coalition defeated dictator Saddam Hussein. In Syria, President Bashar Assad’s deadly crackdown on pro-democracy demonstrators started a civil war. Tunisia and Libya have power vacuums that Islamic militants are exploiting.
• Extremists took advantage of chaos and lawlessness, especially in Syria and Libya, to establish safe havens from which to launch wider operations.
• They exploit YouTube, Twitter and other social media to spread their ideology and draw recruits. Al-Qaida didn’t have anything like that when it was putting together the attacks on New York City and Washington on Sept. 11, 2001.
• Actively promoting their causes as part of a broader religious war, or jihad—instead of battles for control within single nations—attracts recruits from around the world.
• The U.S.-led invasion of Iraq in 2003 stirred resentments that drew new fighters to the extremist cause. Many of those who flocked to Iraq, Afghanistan or Pakistan to train and fight have since returned home, bringing with them military skills, ideological fervour and personal ties to militant networks.
• The historic rivalry between Sunni and Shiite Muslims further inflames the situation. The Islamic State group built its power partly by exploiting Sunni anger at the Shiite-dominated government of former Iraqi Prime Minister Nouri al-Maliki.
• The pace of the violence began to quicken after U.S. forces withdrew from Iraq in 2011. As the situation in Syria disintegrated last year, more violence washed across the border into Iraq.

“Syria has just been the perfect storm,” said Bruce Hoffman, director of the Center for Security Studies at Georgetown University.

Is Al-Qaida behind this?

Al-Qaida is the inspiration, at least.

The terror group’s core leadership has been diminished by American drone strikes and the U.S. raid that killed bin Laden two years ago in Pakistan. The group’s affiliates operate more autonomously today.

Indeed, its most notorious offshoot—the Islamic State group that’s seized a large swath of territory across Iraq and Syria—flatly refused to follow al-Qaida’s lead and was formally expelled in February.

Al-Qaida in the Arabian Peninsula cooked up the failed “underwear bomber” plot to blow up a Detroit-bound airliner on Christmas 2009 and attempted to ship explosive devices into the U.S. on cargo planes in 2010.

Analysts say that group, based in Yemen, is still plotting to strike the American homeland.

Al-Qaida’s affiliate in Somalia, known as al-Shabab, stormed a shopping mall in Kenya last year, killing at least 67 people. A U.S. airstrike on Sept. 1 killed its leader and two other officials; the group has sworn revenge.

The Nusra Front operates in Syria, and al-Qaida in the Islamic Maghreb operates in North Africa. Bin Laden’s successor, Ayman al-Zawahri, recently declared that al-Qaida would expand its reach into India, which has a large Muslim minority.

Other groups have arisen that have ideologies similar to al-Qaida. Among them are Boko Haram, which grabbed the world’s attention by kidnapping more than 300 schoolgirls in Nigeria in April, and Ansar al-Shariah in Libya, one of several militias fighting each other for control in that shattered country.

U.S. and other Western leaders also worry about “lone wolf” terrorists who aren’t part of any group but take inspiration from al-Qaida’s ideology or the Islamic State’s Internet videos to carry out an attack on their homeland.

Another fear: Americans and Europeans drawn to the Middle East to join the fighting may come home as trained terrorists.

Do they all want the same thing?

Al-Qaida, the Islamic State group and sympathetic militants share a common goal: creating a caliphate ruled under their extreme interpretation of Shariah, or Islamic law.

They generally are Salafi jihadis, an extreme minority of Sunnis who say they are the only true followers of the Prophet Muhammad, in the tradition of the earliest Muslims, and advocate holy war to advance their cause. They would severely restrict women, ban music and punish thieves by cutting off their hands.

They oppose democracy and secular dictators alike, because they believe laws are created by God, not kings or voters.

Most Sunnis aren’t Salafis and reject extremist claims.

How do the groups differ?

The jihadists have different priorities.

Al-Qaida grew out of bin Laden’s experiences organizing Muslims to fight the Soviet invasion of Afghanistan, and its first order of business remains chasing Western powers out of the Middle East. That means striking Americans and other Westerners in their homelands or abroad. Establishing a caliphate to unite the world’s Muslims under Shariah comes after that.

As its new name suggests, the Islamic State group is focused on seizing territory and setting up an Islamic state now. It already has declared the lands it seized this summer in Iraq and Syria to be a caliphate and started enforcing its strict interpretation of Islamic law.

Al-Qaida’s leadership broke with the Islamic State group, which was its Iraq branch originally, because of the group’s insubordination in pushing into the Syrian conflict and ruthlessly battling with other jihadi rebels for its own ambitions.

The Islamic State group videotaped its beheading of a British aid worker and two American journalists and said the slayings were retaliation for U.

S. airstrikes against its fighters in Iraq. Unlike al-Qaida, however, the group has yet to reveal a determination to attack within the U.S.

Some jihadists, such as Boko Haram in Nigeria, primarily want to take control of their own countries.

“Most of these groups consider the U.S. an enemy,” Jones said of the various Salafi jihadists. “Most of them are not plotting attacks against the U.S. homeland or U.S. structures like embassies overseas. A few are.”