A Palestinian boy sells candy in Deir Al-Balah, Gaza. The immense poverty and unemployment in Gaza has forced children to look for work. (George Azar)

As a physician, I mourn every time a patient dies. But I know it comes with the territory. Modern medicine cannot cure everyone. But watching a patient die from a curable disease for lack of medicine or for lack of electricity is a pain I am only now learning how to endure.

The Gaza Strip, my home, is confronting a catastrophic humanitarian disaster. Not a natural disaster, but a man-made disaster. The 1.4 million Palestinians in Gaza live in what a United Nations human rights envoy recently called "a prison." Israel's destructive military incursions and total closure of Gaza to the outside world are strangling our fragile economy and demoralizing our society. Israeli tanks and bulldozers have flattened our homes, wrecked our schools and uprooted our orchards. Not even a sack of flour can enter Gaza without Israel's approval.

I am confronted on a daily basis with the consequences of these policies. I watch cancer patients die because we lack the medicines to treat them and Israel forbids them to travel abroad for care. I see dialysis patients growing sicker because we lack electricity for dialysis machines after Israel bombed Gaza's only power plant. I agonize over my hospital's dwindling supplies that cannot be replenished because of the closure and financial crisis. I hear Israeli artillery or gunfire and know my hospital will be overrun with critically injured men, women and children, in desperate need of medical attention that we cannot provide.

My young daughter's friends are terrified to leave their homes. They are traumatized by the Israeli shelling and fearful that they will become that day's innocent victims. As I walk to work, I pass empty markets and shuttered stores, and witness families searching for enough food just to get through the day.

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According to the UN, three-quarters of Gaza's 1.4 million people are dependent on food aid, and over two-thirds live below the poverty level. Recent polls show that more than 85 percent suffer from depression. These figures describe a Gaza I could not have imagined. Though we lived under occupation for decades, we never went hungry. Societal bonds were strong; families, neighbors and friends came to one another's aid. Yet after months of military bombardment, closure and the cutoff of international aid, society is stretched to its limit.

I cannot be the only one who fears where this despair and misery will lead. Surely others must ask what Israel hopes to gain by transforming Gaza into the world's largest open-air prison.

Is Israel's economy threatened by Gaza's impoverished fishermen, who are banned from fishing beyond 100 yards from the seacoast, or by its struggling farmers whose orchards are bulldozed? Do Israelis eat better knowing that one million Palestinians are on the verge of starvation? Will destroying Gaza's infrastructure--its schools, its hospitals, its small businesses--bring Israel lasting peace? Does killing our children somehow make Israeli children safer?

Tragically, Israel has still not learned that its people will never live in peace as long as their neighbors, the Palestinian people, suffer from injustice and oppression.

Despite the clear signs of a humanitarian crisis, and the evidence that Israel is committing collective punishment on a massive scale, the world is mostly silent. World leaders speak often of the need to address the humanitarian crisis in Darfur, but are mute to Israel's relentless campaign to bring the people of Gaza to their knees. Are Palestinians less deserving of the world's concern than other oppressed, brutalized people? Are Palestinian children expendable so long as Israel determines that it is in its interest? Particularly disheartening to Palestinians is the deafening silence from American leaders, who provide Israel with the weapons it uses to inflict destruction on Gaza and the diplomatic cover it uses to avoid opprobrium on the world stage. We know that America has the power and influence to restrain Israel if it only chose to do so.

We are asking America's leaders to live up to the American values of justice, decency and basic human rights. Calling on Israel to allow medical supplies, building materials and food to enter Gaza will not undermine Israel's security. Insisting that Israel refrain from destroying civilian infrastructure and targeting populated areas will not endanger Israeli lives. Persuading Israel to loosen its grip on our borders and allow desperately ill Palestinians to seek medical care abroad will not threaten Israel's existence. These are concrete steps American leaders can take to help bring peace to this region by supporting policies that lead to freedom for all its people.

Mona El-Farra is a physician and human rights advocate in the Gaza Strip. She writes about life in Gaza at http://fromgaza.blogspot.com/.