It's been a good few weeks in what used to be called the war on terror. The main credit here goes to the folks in the intelligence community that our friends on the left love to hate.

Credit goes as well to Barack Obama, who as President has abandoned much of his previous opposition to proven antiterror measures like warrantless wiretaps, and who has only stepped up the campaign of targeted hits on terrorist ringleaders. He's fortunate the Bush Administration left him with a potent intelligence team and the precedent of taking the fight, pre-emptively, to the terrorists on their home turf.

On Monday, U.S. special forces operating in Somalia killed top al Qaeda operative Saleh Ali Saleh Nabhan, believed to have been a planner in the November 2002 bombing of a hotel in Kenya in which 15 were killed. Also killed in recent days was senior al Qaeda leader Ilyas Kashmiri—via a U.S. drone attack in western Pakistan—and Indonesian terrorist mastermind Noordin Muhammad Top, suspected in the July bombing of two Jakarta hotels.

Last week, too, a British court convicted three men for an August 2006 plot to blow up several airliners over the Atlantic. The convictions were obtained largely on the strength of communications intercepts—possibly warrantless—gathered by the U.S. National Security Agency, according to a report by Britain's Channel 4.

All this follows important gains for the Pakistani army in the area of the Swat valley, which fell briefly to the Taliban in the spring. Key among those gains was the August killing—again by a U.S. drone—of Taliban commander Baitullah Mehsud, suspected in the assassination of former Prime Minster Benazir Bhutto. Two of Mehsud's senior deputies were also killed in drone attacks in recent months, while at least eight key al Qaeda commanders have been killed in the last 12 months alone.

For those who were the victims or near-victims of the attacks perpetrated by these men, this is justice. For the rest of us, it is an additional measure of safety. Despite conventional wisdom that killing terrorists only breeds more terrorists and fuels the proverbial "cycle of violence," there is a reason that the U.S. has not been attacked in the eight years since September 11, and that major terrorist plots in Europe have been foiled.

Last week, Britain's Guardian newspaper reported that it had seen interrogation documents showing that European Muslim volunteers "faced a chaotic reception, a low level of training, poor conditions and eventual disillusionment after arriving in Waziristan [Pakistan] last year." It added that there is "evidence that al Qaeda's alliance with the Taliban in Pakistan and Afghanistan is fraying, boosting the prospect of acquiring intelligence that will lead to Bin Laden's capture or death." This from a paper not exactly known as a cheerleader for the use of military force.

The logic of these attacks is simple, even if too many people are reluctant to accept it. Terrorist groups tend to coalesce around charismatic leaders, such as Abimael Guzmán of Peru's Shining Path, Abdullah Ocalan of the Kurdish PKK, or Abu Musab al Zarqawi of al Qaeda in Iraq. Not only are these men difficult to replace, but their death or capture often leads to infighting, disarray and disillusion within the group. As terrorist leaders are forced to spend more time trying to save their own lives, they also have less time to devote to plans for killing others.

None of this means that the war on terror (or whatever you'd like to call it) is anywhere near over. It may never be. But in a struggle in which a day when nothing happens is a victory, it's worth recalling that nothing doesn't happen by accident.