"Some are born great, some achieve greatness, and some have greatness thrust upon them." Ariel Sharon was not born great in February 1928 in the cooperative farming village of Kfar Malal. But he had achieved greatness by the time he died on January 11, 2014, gaining legendary stature as the greatest field commander in the history of the Israel Defense Forces. He was also proud to be a farmer, and he became a dynamic political leader. He lived up to his nickname Arik ("the Lion" in Hebrew) as the Lion of Israel. Not surprisingly, the title of his autobiography was Warrior.

The least that can be said of Sharon is that he was controversial. Everyone recognized him as a strong and robust figure, but critics regarded him as a brutal military commander. From his youth he showed extraordinary personal courage and qualities of leadership. In 1948, aged 20, he led the action in Bir Addas, an Arab village accommodating Iraqi troops. In the action he suffered a bullet in his stomach. Sharon was a key figure, as head of the Unit 101 commando group, in protecting Israel in the 1950s against terrorism. He responded in 1953 to Arab terrorist attacks on Israeli citizens by a raid on the Jordanian village of Qibya where forty houses were destroyed and sixty-nine people killed. Defying military orders in 1956 Sharon sent troops to the Mitla Pass in Sinai; though it was seen as a daring and successful raid, 38 Israeli soldiers were killed.

In the 1967 Six Day War Sharon fought what is now regarded as a classic battle against the Arab stronghold in the Sinai. Again, in 1973 during the Yom Kippur War he exceeded his instructions and led his troops in a daring and successful crossing of the Red Sea into Egypt, and encircled the Egyptian Third Army. Finally, in 1982 his command of troops, then as minister of defense, came to an end with the events in Beirut, Lebanon. During the Lebanese War, whose objective for Sharon was the elimination of the PLO terrorist infrastructure in Lebanon, Christian Phalangists in September 1982 massacred Palestinian Muslims in the refugee camps of Sabra and Shatila in Beirut. Sharon was accused of failing to prevent the massacre, and the Kahan Commission investigating the events held that he was "indirectly responsible" for it.

As a result Sharon was obliged to resign as minister of defense, although his political career continued. As minister without portfolio and minister of trade he concluded the Free Trade Agreement with the U.S. in 1985. While minister of housing, 1990-1992, he initiated and carried out the absorption of immigrants, many from Russia following the fall of the Soviet Union, into Israel, and oversaw the construction of 144,000 apartments. As minister of national infrastructure in 1996 he fostered joint activities with Egypt, Jordan, and the Palestinians.

In 1998 Sharon became foreign minister and met with leaders of a number of countries to advance the peace process. After becoming leader of the Likud party, Sharon became prime minister on February 6, 2001. It is at this point that he, previously the idol of the Israeli hard liners, and the sponsor of settlements, took a dramatic political turn. Sharon was never an ideologue nor a religious individual with an emotional devotion to the concept of the whole area as Eretz Israel. He was always a pragmatic politician, concerned above all with what he considered the strategic interests of Israel.

In this respect he was a "hawk" fighting strongly against threats to Israel's security but he was a realist in recognizing three significant factors: force alone could not end the Arab-Israeli conflict; Jews and Arabs had to live together in the area; and Israel had to take account of international relations and could not, for both security and economic reasons, isolate itself from the world.

Sharon made clear his conviction that Jews and Arabs could live together. Although the State of Israel is Jewish, he held that Arabs should be full citizens in every sense of the word. He also believed, and indeed reiterated it in his last international speech, at the UN in September 2005, that the Palestinians were entitled to freedom and to a national, sovereign existence in a state of their own. He reached out to the Palestinians in a call for reconciliation and compromise.

On becoming prime minister, Sharon announced his determination to seek peace with his Arab neighbors, though he recognized that Yasser Arafat was not a man of peace. He had already in October 1998 signed the Wye River Memorandum, the agreement between Israel and the Palestinians on the West Bank and the Gaza Strip.

It was at the 4th Herzliya Conference on December 18, 2003 that Sharon suggested his Disengagement Plan to end the Israeli presence in the Gaza Strip, a plan he proposed to the cabinet, which adopted it on June 6, 2004. The plan, enforced in August 2005, was to pull out the 10,000 Israelis in the 21 settlements in Gaza, (and four in the West Bank) and then to withdraw all IDF forces and all military installations from the area.

This was a unilateral plan and action by Israel. Sharon in his letter of April 14, 2004 to President George W. Bush explained his position. He accepted the Roadmap for Peace that Bush had proposed in June 2002 as opening a genuine window of opportunity for progress towards a settlement between Israel and the Palestinians, involving two states living side-by-side in peace and security. Unfortunately, the Palestinian Authority had taken no action to fight against the terrorists and to institute real reform, as required under the Roadmap. Terror against Israel had not ceased, and no tangible institutional reforms had taken place.

Believing there was no reliable Palestinian partner with whom Israel could make bilateral peaceful advances towards a settlement, Sharon initiated a unilateral process of disengagement with the hope of reducing friction between Israel and the Palestinians. He hoped that disengagement would stimulate positive changes in the PA that might lead to resumption of direct negotiations.

The essential problem then and now is that the Palestinian leadership has not undertaken a cessation of armed activity, ended all acts of violence against Israelis, or acted against terrorism. Sharon believed that Yasser Arafat wanted to turn a national conflict into a religious one between Islam and Jews. The Palestinian leadership has not undertaken any fundamental political reform. No peace is possible unless the PA ends terrorism and takes action against terrorist organizations. Regrettably, the international community has not succeeded in getting the Palestinians to fulfill their obligations to combat terrorism and effect reforms.

Sharon went into a coma only three months after his UN speech and died before he could continue his search for peace. He would have been gravely disappointed that, after the territorial concessions Israel made on Gaza, the Palestinians would not enter the peace process. Instead, Hamas, the ruling power in Gaza, took advantage of it to wage a war of terrorism.

The hope of many that Sharon's policy could parallel the 1962 policy of French President Charles de Gaulle, who ended the conflict between France and Algeria has not been fulfilled. Both leaders were strong nationalists, both had been regarded, not altogether correctly, as right-wing hard liners, and both had made dramatic shifts in their political views. Sharon had accepted that the idea of a Greater Israel was unrealistic in the same way that de Gaulle had accepted that France could no longer control Algeria.

No one can be sure how Sharon would have reacted to the Palestinian refusal to make concessions and enter into peace negotiations. What is clear, however, is that the Gaza withdrawal he engineered resulted in a shift in Israel's political direction. Israelis are more aware that Palestinians have shown no willingness to make peace with the Jewish State of Israel. The overwhelming lesson learned from Sharon's Gaza policy is that Israel cannot afford to make unilateral concessions on issues or withdrawals from territory unless it is guaranteed in return reciprocal concessions, mainly acceptance of the legitimacy of the State of Israel and the end of terrorism against it. Secretary of State John Kerry ought to learn that lesson and appreciate that the existence and security of Israel depends on this stance.

Michael Curtis is author of Jews, Antisemitism, and the Middle East.