Americans do not, I repeat DO NOT, respond to that fire indiscriminately. When I say "indiscriminately", I mean that even if we can precisely identify the source of the fire (which can be very difficult), we do not respond if we know we will cause civilian casualties. We always evaluate the threat to civilians before responding, and in an urban area the threat to civilians is extremely high. If US servicemen violate those rules of engagement and harm civilians, I assure you we do our best to investigate -- and mete out punishment if warranted. There are differing opinions on the conflict in Iraq, but I am proud of the conduct of our servicemen there.
With that in mind, I find the conduct of the Israeli army in Gaza to be brutal and dishonorable, and it is insulting that they and others claim that the US military would behave in the same way. I know the Israelis are operating under difficult circumstances, but their claim that they follow similar rules of engagement rings hollow; I see little evidence for this claim given the huge number of civilian casualties they have caused from indirect fire.
In particular, I am stunned at the Israeli explanation for the 30+ civilians killed at the UN school. The Israelis say they were responding to mortar fire from the school. Mortars are insidious because their high trajectory and lack of primary flash make it very difficult to trace the source of the fire; you have to have a spotter locate the crew. The Israelis claim that they traced the source of the fire precisely to the school; if so, they must have directly spotted the crew. Thus it is inconceivable that the Israelis did not know that the target was a crowded UN school, yet they chose to fire on the school anyhow. I say without hesitation that this is a criminal act. If the Israelis had said, "sorry, it was an accident", that could indicate a targeting problem, confusion, or inferior training. But to openly admit that they responded reflexively to the Hamas fire without consideration for the inevitable civilian casualties is beyond the pale. The Israelis blame Hamas for firing from the school (although UN personnel on the ground dispute this), but choosing to fire directly at civilians is far worse; it is tantamount to murder. US servicemen do not behave that way in Iraq and Afghanistan, and we face much deadlier adversaries (Hamas mortar crews are apparently not very effective: I believe that all but one of the total Israeli combat fatalities have been from friendly fire). In the rare and unfortunate cases where US personnel have willingly targeted civilians, they have been court-martialed and punished.
The Israeli approach in Gaza strikes me as uncontrolled and vengeful. My objective analysis is that it has little tactical effectiveness; my opinion is that its main goal is to whip the entire Gaza population into submission. This is disturbingly similar to the Israelis' conduct in Lebanon in 2006, so I feel obliged to say that the Israeli military displays a concerted pattern of disregard for civilian lives. I am not a politician, but in my opinion the US should take some sort of political action in this regard. If we continue to formally condone Israel's dishonorable and brutal military conduct in Gaza, I fear there will eventually be dire consequences for our country.
— JDS, North Carolina