At the end of the 1987 movie The Untouchables, Eliot Ness (Kevin Costner) reflects on his transformation over the course of his relentless pursuit of gangster kingpin Al Capone: "I have forsworn myself. I have broken every law I have sworn to uphold. I have become what I beheld, and I am content that I have done right."
Many would say Israel has undergone a similar transformation - from an idealistic nation, resourceful and heroic in its self-defence, to an implacable avenger justifying its ruthlessness by saying its adversaries are even worse.
It's a far cry from plucky little Israel, born in the aftermath of the greatest crime in history, encircled and out-numbered by enemies who seemed reprehensibly indifferent to Jewish suffering.
The West was solidly supportive, partly out of guilt, mostly out of admiration. And with each extraordinary feat of arms, the admiration swelled.
In 1967, Israel trounced the combined forces of Egypt, Jordan and Syria in six days. In 1973, Egypt and Syria attacked without warning on the holiest day in Judaism, yet despite early setbacks it was only the Soviet Union's intervention that saved the Egyptian army from annihilation.
Long before 9/11, Israelis had to learn to live with terrorism. Their ability to endure and respond selectively and precisely was an example America would have done well to follow.
But then the David and Goliath narrative began to pall.
The 1982 invasion of Lebanon ended in a blaze of shame with Ariel Sharon, hero of the Yom Kippur War, having to resign as Defence Minister after his troops facilitated a massacre of Palestinian refugees by Lebanese militias.
This "disgrace" had scant effect on Sharon's political career; in 2001 he became Prime Minister.
Stinging self-defence was replaced by overwhelming retaliation. The level of destruction in the attacks on Gaza and incursions into Lebanon seemed out of all proportion to the original provocation. Entire communities were devastated and displaced as a punishment for having terrorists in their midst.
Yet Israelis should know as well as anyone that one people's terrorist is another people's freedom fighter. The Likud Party that has dominated Israeli politics in recent years is the direct descendant of Irgun, the Zionist terrorist group whose campaign to drive the British and Palestinians out of what is now Israel included the 1946 bombing of the King David Hotel in Jerusalem that killed 91 people.
Two of Irgun's leaders, Menachem Begin and Yitzhak Shamir, went on to become prime ministers.
I don't disbelieve Israeli claims that Hamas has weapons caches in schools and hospitals and Hamas fighters are hiding in plain sight among the civilian population. What I find disturbing is the implication that since Hamas puts the people it claims to represent in harm's way, Israel bears no responsibility for the harm it inflicts on them.
Given its Iron Dome missile protection system and vast military superiority, Israel could choose not to strike those schools and hospitals. Given its resources and tradition of resourcefulness, it could find other ways.
But if the inevitable accusations of anti-Semitism that greet criticism of its ferocious assaults are anything to go by, Israel is now led by people who believe the history of the Jews gives the Jewish state the moral high ground in perpetuity and irrespective of its own actions.
Writing in New York magazine under the headline "Why I have become less pro-Israel", Jonathan Chait spoke for many when he spelt out the reasons for his alienation: the disproportionateness of Israel's military responses which, in propaganda and diplomatic terms, plays into Hamas's hands; the lack of any strategy beyond force and more force; the fact that Israel has effectively become a one-party state in which the voice of moderation has been reduced to a cry in the wilderness.
We shouldn't forget that, unlike them, Israel has never vowed to wipe its enemies off the map even though, again unlike them, it could do so.
But in its eagerness to deploy its high-tech firepower against defenceless people living in desperately straitened circumstances, in the hectoring self-righteousness of Prime Minister Benjamin Netanyahu, in the nauseating spectacle of Israelis gathering on a hillside with cartons of popcorn to watch their missiles and shells fall on Gaza, Israel is barely recognisable as the country it once was.
Israel and its "Israel right or wrong" supporters are absolutely correct to say its critics are holding it to a higher standard than its enemies.
The fact that Israel had higher standards than its neighbours was largely why we supported it in the first place.