From the Jerusalem Post:

Israel did not violate the laws of war and made marked improvements in its fighting capability during the recent military operation against Hamas in Gaza, yet the gains from the conflict in the long term remain uncertain, a US study concludes.
The analysis of the 22-day conflict in Gaza by Anthony H. Cordesman of the Center for Strategic and International Studies finds “impressive improvements in the readiness and capability” of the Israeli Defense Forces since the war against Hizbullah in Lebanon in 2006, and unequivocally states that Israel did not violate the laws of war despite the large number of civilian casualties among the Palestinians.
“[Israel] did deliberately use decisive force to enhance regional deterrence and demonstrate that it had restored its military edge,” the report states. “These, however, are legitimate military objectives in spite of their very real humanitarian costs.”