Like Osama bin Laden, his predecessor as leader of al-Qaida, Ayman al-Zawahri had the blood of thousands of innocents on his hands. His death, announced by the White House on Monday, should be welcomed not just in the United States but everywhere his terrorist organisation has wrought havoc over the past decades.

Zawahri’s killing was a feat of patient, effective intelligence work. US spies tracked him through his family to Kabul earlier this year, then spent months confirming his presence and observing how he spent his days. That information allowed an American drone to target him while he was standing alone on his balcony; the two Hellfire missiles that took him out killed no one else, according to US officials. In announcing the strike, Joe Biden was right to pay tribute to the intelligence professionals who spent decades tracking down the Egyptian terrorist leader and who devised the plan to eliminate him.

There was no doubt he had it coming. In addition to helping plot the September 11 terrorist attacks — which he called a “victory” in 2002 — Zawahri had a hand in the 1998 bombings of US embassies in Kenya and Tanzania, which killed more than 200 people; the 2000 attack against the USS Cole, which took the lives of 17 US sailors; the 2005 London transit bombings, which killed 52 civilians; and numerous other atrocities. Few terrorists of his generation were responsible for more bloodshed.

While assessments of al-Qaeda’s remaining strength vary, Zawahri had been its best-known remaining leader and a rallying point for its affiliates in Africa, the Middle East and South Asia. Although lacking in Bin Laden’s charisma, he had managed to keep those offshoots within the fold despite efforts by Islamic State to win them over. Zawahri himself was continuing to encourage attacks against the US; the affiliates he cultivated remain a threat to carry them out.

The strike suggests two further lessons.

First, it is difficult but not impossible for the US to gather intelligence, conduct surveillance and eliminate terrorist threats in Afghanistan despite having ceded the country to the Taleban a year ago. Biden pledged at the time to use such “over-the-horizon” operations to keep Americans safe. His administration should redouble efforts to improve its capabilities by working out overflight and basing agreements with Afghanistan’s neighbours, while expanding intelligence co-operation with Pakistan, India and others worried about extremist groups being sheltered by the Taleban.

Second, the Taleban clearly cannot be trusted to uphold its promises to prevent terrorist groups from using Afghanistan as a base. Zawahri was apparently living under the protection of the Haqqani branch of the Taleban; US officials say Haqqani operatives spirited away Zawahri’s family after the strike to eliminate evidence of his presence. At the very least, those open links violate the spirit of the Doha Agreement, which paved the way for the US withdrawal. The Taleban have been pursuing aid and international recognition ever since; they should receive neither as long as they continue to coddle terrorists.

For now, it is enough to say that justice has been served — and that the world is a safer place with Ayman al-Zawahri in his grave.