"The old order changeth, yielding place to new," wrote the British poet Alfred Lord Tennyson. Israel as it celebrates its 50th anniversary is a different state from the one we had known in the past. It has changed almost beyond recognition, physically and mentally, with new and different aspirations and priorities, new and different problems that can only be tackled successfully if we know how to adjust ourselves to the changes. The recipes for success in the past will not necessarily work in the new Israel as it enters its 51st year.

Every country has its own bedrock national goals, which form the basis for its policy orientations. Israel's national goals can be divided into four categories: peace and security, economic well-being, political consolidation, and the implementation and fulfillment of Zionist ideals. The latter form the foundation of the existence of Israel as a state.

These four sets of goals have acted as signposts that have guided every one of our governments for the past 50 years. They were as valid for Menachem Begin as they were for David Ben-Gurion, for Yitzhak Shamir as they were for Shimon Peres. Yet each one interpreted these goals differently, put different emphases and different orders of priorities according to his or her ideological beliefs, and according to changing times and circumstances.

The most urgent needs of the fledgling state, buffeted by ill winds from all sides during the days of Ben-Gurion, were certainly different from the demands of today. Although the goals have remained unchanged, the means of achieving them and the order of priorities have undergone a metamorphosis not only because of the different Israel that exists today but also because of the changing world beyond our borders.

A successful government is one that knows how to choose the best means, in a logical order of priorities, to achieve the national goals. Ben-Gurion correctly put the emphasis on the third and fourth categories: the consolidation of the political legislation of Israel as a state and the ingathering of the exiles from the four corners of the world. Begin correctly seized the opportunity for moving forward toward the first set of goals when he went to Camp David and agreed to pay a heavy price for the sake of peace with Egypt.

Golda Meir missed that opportunity, for she misread the political map after the Six-Day War in 1967. She could have then moved toward a peaceful solution with the Palestinians, but her priorities were wrong and she did not understand how to exploit the changing circumstances in order to achieve our national goals.

At that time, Yasser Arafat's Palestine Liberation Organization had only been in existence for two years, and was not yet a force to be reckoned with in the West Bank and Gaza. There was a strong hard-core element among the Palestinians in those territories who were willing to come to terms with us. We chose to ignore them, and, as a result, opened the door wide to enable the most extreme among the PLO to take over.

Meir's mistakes cost us dearly in blood that was spilled unnecessarily and in a wasted opportunity to bring an end, or at least to limit, the conflict with our neighbors. Thirty years later that opportunity has again arisen, and we stand once again on the threshold of advancing toward one of our major national goals, the attainment of peace with security.

The circumstances today are much more favorable than they were in 1967: There is no longer a hostile Soviet Union to sabotage and undermine our peace efforts, the Arab world no longer negates our very existence and Israel itself is much stronger than it was then, militarily and economically.

Then, as now, there were Palestinians who were willing to make peace with us, but this time they represent the majority of the Palestinian people, backed by the PLO itself and by a large part of the Arab world. Will we ignore the challenge now as we did then?

A good government is measured by its ability to adapt to changing circumstances in order to achieve its national goals. We have in our grasp today the possibility of achieving peace with security. It must be understood that there will not, cannot, be security without peace. The two go together. Peace can be fashioned in a manner that will uphold our security, but security without peace is nonexistent.

The circumstances today enable us to reach that goal. If our government fails to exploit these circumstances, it will bring tragedy to our people. In generations to come, our children and grandchildren will bemoan the fact that because of a bad government, Israel missed the chance of attaining one of its most important goals, peace with our neighbors and security. We must not allow that to happen.