Like I've written below, suicide attacks have been used for a long time. When nothing else works, a suicide attack can often be an effective way to strike your enemies.

During WWII, thousands of Japanese committed suicide in attacking Allied warships. They switched to this tactic in 1944 because their conventional dive bombing and torpedo plane attacks were rendered ineffective by our anti-aircraft defenses. According to this source,

"In peace and affluence, we have shuddered with revulsion at Hiroshima, but forget what suicidal fanaticism at Okinawa had weeks earlier taught Americans of that age — 2,000 kamikaze attacks, 34 ships sunk, 368 damaged, over 12,000 American dead, 35,000 more wounded, along with 100,000 Japanese killed and another 100,000 civilian casualties, all in hand-to-hand fighting to take an island miniscule in comparison to the far better defended and armed Japanese mainland."

The Tamil Tigers have used suicide bombers since the early 1980s. They've managed to kill a lot of people that way. It's a lot harder to get into a secure location, set a bomb, then escape than it is to penetrate security and detonate close to your target.

I've heard several interviews with Secret Service agents who describe how difficult it is to stop a lone gunman, especially one who isn't afraid to die. A lone suicide bomber can be far more deadly than a gunman.

It wouldn't surprise me in the least if the Taliban switches to suicide bombers. They're very difficult to stop. I suspect they hope to kill a lot of Americans until we tire of the war and go home like we did in Vietnam and Lebanon.