Chilling testimony by Israeli soldiers substantiates charges that Israel's Gaza Strip assault entailed grave violations of international law.  The emergence of a predominantly right-wing, nationalist government in Israel suggests that there may be more violations to come.  Hamas's indiscriminate rocket attacks on Israeli civilians also constituted war crimes, but do not excuse Israel's transgressions.  While Israel disputes some of the soldiers' accounts, the evidence suggests that Israel committed the following six offenses:

• Violating its duty to protect the civilian population of the Gaza Strip.  Despite Israel's 2005 "disengagement" from Gaza, the territory remains occupied.  Israel unleashed military firepower against a people it is legally bound to protect.

• Imposing collective punishment in the form of a blockade, in violation of Article 33 of the Fourth Geneva Convention.  In June 2007, after Hamas took power in the Gaza Strip, Israel imposed suffocating restrictions on trade and movement.  The blockade -- an act of war in customary international law -- has helped plunge families into poverty, children into malnutrition, and patients denied access to medical treatment into their graves.  People in Gaza thus faced Israel's winter onslaught in particularly weakened conditions.

• Deliberately attacking civilian targets.  The laws of war permit attacking a civilian object only when it is making an effective contribution to military action and a definite military advantage is gained by its destruction.  Yet an Israeli general, Dan Harel, said, "We are hitting not only terrorists and launchers, but also the whole Hamas government and all its wings."  An Israeli military spokeswoman, Maj. Avital Leibovich, avowed that "anything affiliated with Hamas is a legitimate target."

Israeli fire destroyed or damaged mosques, hospitals, factories, schools, a key sewage plant, institutions like the parliament, the main ministries, the central prison and police stations, and thousands of houses.

• Willfully killing civilians without military justification.  When civilian institutions are struck, civilians -- persons who are not members of the armed forces of a warring party, and are not taking direct part in hostilities -- are killed.

International law authorizes killings of civilians if the objective of the attack is military, and the means are proportional to the advantage gained.  Yet proportionality is irrelevant if the targets of attack were not military to begin with.  Gaza government employees -- traffic policemen, court clerks, secretaries and others -- are not combatants merely because Israel considers Hamas, the governing party, a terrorist organization.  Many countries do not regard violence against foreign military occupation as terrorism.

Of 1,434 Palestinians killed in the Gaza invasion, 960 were civilians, including 121 women and 288 children, according to a United Nations special rapporteur, Richard Falk.  Israeli military lawyers instructed army commanders that Palestinians who remained in a targeted building after having been warned to leave were "voluntary human shields," and thus combatants.  Israeli gunners "knocked on roofs" -- that is, fired first at corners of buildings, before hitting more vulnerable points -- to "warn" Palestinian residents to flee.

With nearly all exits from the densely populated Gaza Strip blocked by Israel, and chaos reigning within it, this was a particularly cruel flaunting of international law.  Willful killings of civilians that are not required by military necessity are grave breaches of the Geneva Conventions, and are considered war crimes under the Nuremberg principles.

• Deliberately employing disproportionate force.  Last year, Gen. Gadi Eisenkot, head of Israel's northern command, speaking on possible future conflicts with neighbors, stated, "We will wield disproportionate power against every village from which shots are fired on Israel, and cause immense damage and destruction."  Such a frank admission of illegal intent can constitute evidence in a criminal prosecution.

• Illegal use of weapons, including white phosphorus.  Israel was finally forced to admit, after initial denials, that it employed white phosphorous in the Gaza Strip, though Israel defended its use as legal.  White phosphorous may be legally used as an obscurant, not as a weapon, as it burns deeply and is extremely difficult to extinguish.

Israeli political and military personnel who planned, ordered or executed these possible offenses should face criminal prosecution.  The appointment of Richard Goldstone, the former war crimes prosecutor from South Africa, to head a fact-finding team into possible war crimes by both parties to the Gaza conflict is an important step in the right direction.  The stature of international law is diminished when a nation violates it with impunity.