Israel is under fire for allegedy using white phosphorus shells in Gaza 9http://www.timesonline.co.uk/tol/news/world/middle_east/article5519433.ece). WP (known to Vietnam GIs as Willy Pete) is normally used to create billowing white smokescreens 9http://en.wikipedia.org/wiki/White_Phosphorous). But it’s also a hideously effective anti-personnel weapon. If it lands on human skin, it burns through to the bone, and it’s very hard to extinguish. U.s. and British forces used it in Iraq in 2004.
Willy Peter seems to be permitted under international law as long as it’s used to protect friendly troops, such as by creating smokescreens. But there’s a question of whether it can be used in populated areas where civilians can be hit by phosphorus. This is a prime example of why international law tends to be ineffective at restricting use of weapons. If the battlefield is a city (and Hamas has deliberately chosen to hide among itself among civilians), then how can tactically useful weapons be employed without harming civilians? No soldier wants to run down the street in full view of snipers without a nice, thick smokescreen to cover him. On the other hand, do we really want to say that in war, anything goes?