The Proportionality of the Gaza Action
Under the Geneva Conventions, nations are required to respect proportionality in dealing with their enemies particularly in civilian areas. Proportionality is somewhat subjective but basic numbers can provide some guidance as to what is within the bounds of reasonableness.
The Israeli Government has explained the need for their current actions based on rockets that are threatening its citizens. Since 2001, rockets have killed 18 Israeli citizens. In the last 10 days 600 Gaza residents have died. This means that in 7 years an average of 0.01 people per day have been killed by rockets. If you chart this against the 60 / day that have died in Gaza the ratio rounds off to 100% to 0%.