http://news.bbc.co.uk/1/hi/7811386.stm
The International Committee of the Red Cross - guardian of the Geneva Conventions on which international humanitarian law is based - defines a combatant as a person "directly engaged in hostilities".
But Israeli Defence Forces spokesman Captain Benjamin Rutland told the BBC: "Our definition is that anyone who is involved with terrorism within Hamas is a valid target. This ranges from the strictly military institutions and includes the political institutions that provide the logistical funding and human resources for the terrorist arm."
Philippe Sands, Professor of International Law at University College London, says he is not aware of any Western democracy having taken so broad a definition.
"Once you extend the definition of combatant in the way that IDF is apparently doing, you begin to associate individuals who are only indirectly or peripherally involved… it becomes an open-ended definition, which undermines the very object and purpose of the rules that are intended to be applied."
Indeed, Hamas itself has been quoted as saying the fact that most Israelis serve in the military justifies attacks on civilian areas.