The "radicals" in Yemen are primitive tribal people. Pakistan and Saudi Arabia have both shown that those people are easily managed through peaceful means. All of the evidence, 100%, indicates that these groups are being deliberately prodded and provoked, rather than being dealt with in a way to reduce their violence. Today there was another significant drone strike and also today an American aircraft buzzed the capitol Sanaa very overtly. So the central question in Yemen really is why are we trying to provoke these tribal people into becoming a threat that they otherwise would not be.
from the article: U.S. tells citizens: Leave Yemen immediately