Washington — White House counterterrorism adviser John Brennan says current intelligence indicates that morale is low among members of the terrorist group al-Qaida and many of its members are giving up and returning home, believing it is a fight they will never win.

“In short, al-Qaida is losing badly,” says John Brennan, assistant to the president for homeland security and counterterrorism.

Brennan addressed the threat posed by al-Qaida in the year since its leader, Osama bin Laden, was brought to justice during a night raid on his compound in which he was killed. He told a Washington conference April 30 that al-Qaida has suffered heavy losses of its leadership so quickly that the group has had difficulty replacing them, and those chosen continue to make mistakes and give away operations before they can be started. Brennan said the United States and its allies and partners have been unrelenting in efforts to track, capture or destroy al-Qaida and its operatives wherever they are found to be operating.

For all of these reasons, Brennan said in remarks at the Woodrow Wilson International Center for Scholars, it has become “harder than ever” for al-Qaida’s core to plan and execute large-scale, potentially catastrophic attacks against the U.S. homeland.

“Today, it is increasingly clear that, compared to 9/11, the core al-Qaida leadership is a shadow of its former self,” Brennan said. “Al-Qaida has been left with just a handful of capable leaders and operatives, and with continued pressure is on the path to its destruction.”

But Brennan warned that while the al-Qaida core has disappeared, many of its affiliate groups and adherents continue to carry on the cause with extreme violence. For example, he said, elements of al-Qaida have merged with al-Shabaab in Somalia, but its focus is primarily on launching regional attacks while both organizations are in a steady decline.

In Yemen, al-Qaida in the Arabian Peninsula (AQAP), which was weakened by the death last year of Anwar al-Awlaki, its leader of external operations and chief planner, continues to be al-Qaida’s most active affiliate, Brennan said. That is part of the reason the United States continues providing support to the government of Yemen in its efforts against AQAP, which is being forced to fight for the territory it needs to plan attacks beyond Yemen.

Brennan said another al-Qaida affiliate, al-Qaida in the Islamic Maghreb (AQIM), continues its efforts to weaken regional governments and engages in kidnapping of Westerners for ransom to fund its terrorist agenda.

More broadly, al-Qaida’s killing of innocents — particularly Muslim men, women and children — has badly damaged its image and appeal to Muslims around the world, he added.

Despite the great progress that has been made against al-Qaida, the threat has not passed, Brennan said in prepared remarks made available by the White House to journalists. Al-Qaida and its affiliates still are intent on attacking the United States, he said. But the damage inflicted on al-Qaida’s leadership combined with how it has alienated itself in much of the world has given the United States and its partners and allies reason to look forward.

“If the decade before 9/11 was the time of al-Qaida’s rise, and the decade after 9/11 was the time of its decline, then I believe this decade will be the one that sees its demise,” Brennan said. “This progress is no accident. It is a direct result of intense efforts over more than a decade, across two administrations, across the U.S. government and in concert with allies and partners.”

The United States and its partners have been using every element in its pursuit of terrorist groups, which includes the power of U.S. values and commitment to the rule of law, Brennan said. Attorney General Eric Holder has discussed how U.S. counterterrorism efforts are rooted in and strengthened by adherence to the law, and Defense Department general counsel Jeh Johnson has addressed the legal basis for military efforts against al-Qaida. And Stephen Preston, the general counsel at the CIA, has discussed how the intelligence-gathering agency operates under U.S. law here and abroad, Brennan said.

As a result, the United States has been open regarding its counterterrorism policies and their legal justification, Brennan said. “As a matter of international law, the United States is in an armed conflict with al-Qaida, the Taliban and associated forces, in response to the 9/11 attacks, and we may also use force consistent with our inherent right of national self-defense,” he said.

Brennan added that the U.S. Congress authorized the president “to use all necessary and appropriate force” against those nations, organizations and individuals responsible for 9/11 in the course of responding to the terrorist attacks nearly 11 years ago.