A recent incident in Afghanistan shows once again why the United States should maintain the Guantanamo Bay, Cuba, detention facility for suspected terrorists captured abroad.

Back in 2007, suspected al-Qaida terrorist Sabar Lal Melma was set free from "Gitmo."

But like scores of others who have left Gitmo, Melma again began fighting on behalf of the al-Qaida terrorist network and against the United States.

And so, just weeks ago, U.S. forces found and killed Melma in a compound in Jalalabad, Afghanistan.

But how much harm did he do in the intervening years after he was freed from Gitmo but before he was found again by American forces?

We may never know the answer to that painful question.

But what we do know is that Gitmo serves a vital purpose in our fight against terrorists. Calls to shut it down and heedlessly free its detainees should be resisted.