TODAY, as American, European, Russian and United Nations officials meet in Washington to discuss the future of the Middle East peace process, Israel�s prime minister, Benjamin Netanyahu, remains adamant that a peace deal premised on returning to Israel�s pre-1967 borders poses an unacceptable risk to its security.

He is right: the country�s 1967 borders are not militarily defensible. But his use of this argument to reject the only viable formula for Israeli-Palestinian peace � a negotiated two-state solution based on mutually agreed upon land swaps � is wrong, and it does not serve Israel�s security interests.

Israel needs peace with the Palestinians, and that will likely require a return to the 1967 lines with a few adjustments. These borders can be made defensible if they come with a security package consisting of a joint Israeli-Palestinian security force along the West Bank�s border with Jordan, a demilitarized Palestinian state and a three-way Israeli-Jordanian-Palestinian defense treaty. Combined with such a package, the balanced formula President Obama outlined in his May 19 speech can give Israel the security it needs and deserves.

Until June 1967, Israelis feared that a swift Arab military move could cut Israel in two at its �narrow waist� � an area near the city of Netanya, where the country is less than 10 miles wide. By doing so, Arab tanks and artillery could have reached Tel Aviv within a few hours. In the 44 years since, the geography has not changed, but the threat has.

Today, there is a new menace that we did not face in 1967. Short- and medium-range rockets, mortars and missiles supplied by Iran are making the lives of Israeli civilians a nightmare. Thousands of these rockets have been launched from Gaza into Israeli towns and villages since Hamas wrested control of Gaza in 2007; and if an independent Palestine emerges on the West Bank, these weapons could find their way there, too.

That is why the border between the West Bank and Jordan must be made impenetrable. This cannot be done remotely, from the 1967 lines; it will require a joint Israeli-Palestinian military presence along the Jordan River. Such joint military activity would not violate Palestinian sovereignty and could be modeled on Israel�s current coordination with Palestinian security forces in the West Bank. It would be far more effective than deploying an international force. After all, United Nations forces in southern Lebanon have failed to prevent a colossal military build-up by Hezbollah since Israel withdrew from the area in 2000.

Second, the Palestinian state must be demilitarized. No tanks, artillery or missiles can be deployed within its boundaries. In the absence of this weaponry, international guarantees will ensure Palestine�s security and territorial integrity.

Third, an Israeli-Jordanian-Palestinian defense treaty is necessary to safeguard their common strategic interests. Joint military planning and sharing early warning systems to prevent threats from Iran, its proxies and other jihadist forces in the region would cement this treaty.

This security package would make the 1967 borders defensible, and keep Palestine from becoming another launching pad for terror. Moreover, an Israeli-Palestinian agreement would bring about a dramatic, strategic change in the Middle East. It would remove the obstacle preventing moderates in the region from uniting against militant Islamist extremists and lay the groundwork for a new strategic alliance in the region, including the Persian Gulf countries, which are natural business partners for Israel, Jordan and Palestine.

As a result, Israel would be able to extend its hand to new democratic and secular governments in the Arab and Muslim world. And those committed to Israel�s destruction would be confronted by a new alliance with enormous economic and military power.

I have devoted more than three decades of my life to defending Israel, from the Litani River in Lebanon to the western bank of the Suez Canal in Egypt, and I would never support irresponsible, hazardous solutions to Israel�s security problems. I don�t believe durable peace in the region is possible unless Israel remains the strongest military power between Tehran and Casablanca.

We have no choice but to protect ourselves in a perilous world of aggressive Islamist fanatics and complacent, confrontation-averse Western democracies. But nurturing settlements in the West Bank and maintaining an occupation in order to protect them is not the proper way to do it.

Following that path will lead to disaster. Israel could become a binational state of first- and second-class citizens at war with each other; a third Intifada could break out, damaging Israel�s economy and destroying Palestine�s nascent infrastructure; or the pro-negotiation policy of the Palestinian president, Mahmoud Abbas, could collapse, allowing Hamas to take power in the West Bank. If this happens, the doomsday prophecy of rockets raining down on Ben-Gurion International Airport just might be fulfilled.