THE POSITION WITH THE WORST JOB SECURITY ON THE PLANET…. There should probably come a point in every terrorist’s life when he or she learns of a vacancy as al Qaeda’s #3 leader, and thinks, “Maybe I won’t apply for this one.” After all, the careers of al Qaeda’s #3 leaders are invariably nasty, brutish, and short.

The operational leader for Al Qaeda in Afghanistan was killed in an American missile strike in Pakistan’s tribal areas in the last two weeks, according to a statement the group issued late Monday that American officials believe is correct.

The militant leader, Mustafa Abu al-Yazid, an Egyptian, was a top financial chief for Al Qaeda as well as one of the group’s founders, and was considered by American intelligence officials to be the organization’s No. 3 leader, behind Osama bin Laden and his deputy, Ayman al-Zawahri, another Egyptian. […]

A United States official said American intelligence analysts believed the statement from Al Qaeda was accurate. They said the death of Mr. Yazid, also known as Saeed al-Masri, was a significant setback to Al Qaeda’s ability to help plan and support cross-border attacks against American and allied forces in Afghanistan from its haven in Pakistan’s tribal areas.

I don’t doubt for a moment that this is a very important development, and every time al Qaeda loses a key leader, it’s encouraging. I don’t intend to make light of this. On the contrary, U.S. officials are to be commended for another counter-terrorism success story. Yazid was considered to the overall commander for the terrorist network in Afghanistan and Pakistan. His death is a key victory.

But it’s also hard not to notice there sure are a lot of people who become al Qaeda’s #3 leader, and they don’t last long in the position. Several years ago, I counted the number of times the #3 man in al Qaeda had been killed, and I found six individuals. Last year, Gawker kept the count going, and found three more. Unless I’m missing any, that would make Mustafa Abu al-Yazid the tenth al Qaeda #3 to meet his demise.

That does not, however, take away from the significance of this. A U.S. official characterized Yazid as the terrorist group’s “chief operating officer, with a hand in everything from finances to operational planning. He was also the organization’s prime conduit to bin Laden and Zawahri.” The developments come on the heels of U.S. forces killing Abu Ayyub al-Masri, the leader of Al Qaeda in Iraq, and spiritual leader Abu Omar al-Baghdadi, in April.

It’s part of what I consider one of the best-kept secrets in American politics: the Obama administration’s recent successes on counter-terrorism. Mullah Abdul Ghani Baradar, the Taliban’s top military commander, was captured. High-profile terrorists have been killed — Hakimullah Mehsud, Baitullah Mehsud, Saleh Ali Saleh Nabhan — while many more have been arrested — Najibullah Zazi, Talib Islam, and Hosam Maher Husein Smadi.

I’m sure Rudy Giuliani and Liz Cheney will be along any minute now to tell us that these developments are a sign of weakness, but they’ll no doubt sound pretty foolish.

Steve Benen

Follow Steve on Twitter @stevebenen. Steve Benen is a producer at MSNBC's The Rachel Maddow Show. He was the principal contributor to the Washington Monthly's Political Animal blog from August 2008 until January 2012.