But, CBS News National Security Correspondent David Martin reports, their growing use is drawing fire from critics.
U.S. officials claim CIA drone strikes in Pakistan have eliminated more than 500 terrorists over the past two years while killing only 30 civilians. Impressive numbers, but there is no way to verify them because no one will officially admit the strikes are taking place.
Phillip Alston is the author of a new United Nations report which argues that drone strikes amount to a "license to kill" without being held accountable -- a license the U.S. would not want any other country to have.
"The rules we're setting for ourselves now are the rules that we're also setting for others later," Alston said.
Think about it - an operation the U.S. government doesn't even admit exists has killed more than 500 people.
Peter Singer of the Brookings Institute has counted 137 drone attacks.
"It allows us to carry out acts of war without having to go through some of the debates that we would have in the past," Singer said.
U.S. officials say those attacks have killed sixteen high ranking terrorists -- most recently al Qaeda's number three,along with hundreds of foot soldiers and trainers.
"I think they've been very effective at killing a large number of very bad guys," Singer said.
The strikes are increasing in intensity as a new-generation drone, called the Reaper, which can carry twice as many weapons, comes on line with even more sophisticated cameras.
The strikes - in Pakistan's tribal areas - are secret because neither the U.S. nor Pakistan wants to admit that the CIA routinely violates Pakisitani sovereignty. But everybody knows who to blame.
Singer said the strikes have been "very effective in creating a large amount of anger at the U.S. that may well bite us in the long term."
Faizal Shahzad, the Times Square bomber, told investigators the drone strikes were the reason he set out to kill hundreds of innocent Americans. To which, U.S. officials say, the purpose of the strikes is to kill the Shahzad's of this world before they ever leave Pakistan.