The toppling of Egypt's modern-day pharaoh through peaceful mass protests, aided by Facebook and Twitter, marks a watershed for Egypt and the entire Arab world. Contrary to widespread anxieties in the U.S. foreign policy establishment, it will also serve the long-term interests of the United States - and Israel.

Many analysts of Egypt have been warning for years that the status quo under Hosni Mubarak was not sustainable. A repressive and deeply corrupt dictatorship was sitting on top of a social volcano - an increasingly young, urbanized, digitally connected population seething over the lack of freedom, dignity and economic opportunity. A quarter of Egypt's working-age youth are unemployed and many more under-employed. Over the past two decades, average incomes in Egypt stagnated while they doubled or tripled elsewhere in the region.

Think of what could have happened. Many observers (including myself) worried that the growing alienation of young Egyptians might flow in anti-American, anti-Israeli and radical Islamist directions. The inevitable eruption could have turned violent, resulting in the kind of bloody suppression that gripped Algeria in the early 1990s, when 200,000 died. Or it might have been hijacked by radical Islamists who would ride the popular revolution to power, as in Iran in 1979.

So far, none of these have happened. The millions of Egyptians who have poured into the streets of Cairo and other cities have not been chanting "down with America," nor have their protests been about Israel (or the Palestinians). Rather, they want freedom, justice and accountability in Egypt. They have mobilized for democratic change with extraordinary discipline, imagination and moderation. In the face of killings, provocations, arrests and torture, they have adhered to nonviolence as a sacred principle.

In achieving the first condition for Egypt's liberation, the departure of the pharaoh, through peaceful grassroots mobilization, a huge chip has been lifted from their shoulders. Now Egyptians feel a new sense of pride, confidence and empowerment. And they are beginning to view the United States in a fresh and more hopeful light, not because of President Obama's Cairo Speech in 2009 but because of what he said and subtly did in the last two weeks (after several rhetorical blunders by some in his administration). As the mass protests grew, Obama aligned the United States more explicitly behind the goal of peaceful democratic change, warned the regime against the use of force, and urged Mubarak to step aside. The experience could mark a turning point not just for Egypt but for Barack Obama personally. He now has the chance to nurture democratic change in the Arab world through artful diplomacy and timely assistance, where George W. Bush failed with blunter rhetoric and means.

Israel as well should be reassured by developments so far. Egypt's new (and hopefully temporary) military junta has quickly reaffirmed the country's treaty obligations. Few protesters are calling for abrogation of Egypt's peace with Israel. Most protesters resent Israel's treatment of the Palestinians and want an independent Palestinian state, but mainly they want to transform their own country politically and economically. They know their aspirations for human dignity and economic opportunity can only be met with far-reaching internal reforms, and that the worn-out theme of anti-Zionism is a divergence from that. Israel and its friends should thus welcome democratic change in Egypt. The only way to guarantee a lasting Middle East peace is to root negotiated agreements in the same democratic legitimacy that undergirds the stability and resilience of Israel's political system. As Thomas Friedman recently observed, it is a better bet to make peace with 82 million people than with one man.

The challenge now is to ensure that Egypt's revolution produces a genuine pluralist democracy. This is far from assured.

Egypt's military rulers may well seek to sabotage the transition and restore the old order with a slightly more democratic façade. Or the Muslim Brotherhood (which rejects violent means but clings to Islamist political ends) could gain the upper hand in popular mobilization or elections. But the second scenario will be much more likely to follow, rather than prompt, the first. If a democratic transition unfolds seriously and peacefully through negotiations and reform, and if democratic institutions are well designed, the Muslim Brotherhood will be a significant but minority player.

For Egypt, Mubarak's fall is only the first step along a tortuous path. If its transition leads to democracy, it will produce a much more reliable partner for peace and progress in the Middle East. That is why other democracies in the world should support it in every way possible.

There are more laws and international treaties designed to protect human rights in conflict zones than ever before. Yet civilians continue to pay the ultimate price, with women and children frequently caught in the crossfire. At the beginning of the 20th century, there was one civilian casualty for every eight or nine military casualties, said Richard Goldstone, the South African jurist who played a key role in helping his country overcome apartheid, served as the chief prosecutor of the International Criminal Tribunals on Rwanda and the former Yugoslavia, and became a household name in 2009 for his controversial fact-finding mission after an Israeli offensive in the Gaza Strip. During World War II, the ratio increased to 1-to-1. Today, after what was, Goldstone said, a "very bloody century," every combatant casualty is matched by nine civilian deaths.

What explains this? Goldstone joined Stanford historian James Campbell and Peter Berkowitz, a political scientist, to grapple with this paradox as part of Stanford's Ethics and War Series, co-sponsored by the Center for International Security and Cooperation.

One reason behind this seeming disconnect is that gaping anomalies remain in the international legal system. It is a "very recent development that international laws have been designed to protect civilians and civilian objects," said Goldstone. Another cause of the paradox is that the most critical issue in determining whether the death of a civilian constitutes a war crime is highly subjective. The so-called principle of proportionality, defined by the Law of Armed Conflict, requires that parties refrain from attacks resulting in excessive civilian casualties. But it is up to "reasonable commanders" to judge whether such violence is justified, said Berkowitz, a senior fellow at the Hoover Institution.

Compounding the problem is that in many of the nations where crimes against civilians may have been committed, there is little interest or even open hostility toward allowing international fact-finding missions to make an assessment. Moreover, many of the transnational organizations designed to help protect civilians simply fail to do so. Goldstone said the UN should be commended for assisting the injured in Gaza but "stands condemned for ignoring the plight of Tamils."

A better system might include requiring greater education in military affairs for human rights lawyers, Berkowitz said. Goldstone's report on the Gaza conflict, Berkowitz argued, failed to properly evaluate whether the civilian cost was a military necessity, noting that Goldstone did not assess whether "reasonable" Israeli commanders had intended to avoid civilian casualties. A better understanding of military procedure, Berkowitz suggested, might have helped Goldstone and others in a similar situation make that kind of assessment.

The United States may also have a role to play in filling in the gaps in the international justice system. Campbell said that the Geneva Convention of 1949, which extended legal protection to war victims, was largely an American construction. Indeed, Berkowitz said that America has "special burdens" to spread liberal democracy across the world. However, the U.S. was reluctant to sign the Convention on the Rights of the Child, ratified by 194 U.N. nations that would protect women and children, said Helen Stacy, a senior fellow at the Center for Democracy, Development, and the Rule of Law.

How some of these issues will be resolved is still an open question. Human rights laws are complex and evolving, said Campbell. "Just as freedom is a constant struggle, so is international humanitarian law," he said. The important part was that the legal system continues to grapple with these issues. The struggle toward an effective system of international justice is being "waged in our country," he said, "in dialogues like the ones we are having today."