The current crisis between Israel and the United States is fundamental and serious. Even if a nominal solution is found, it will be temporary, until the next one, which won't be far off. These crises are harmful to our national interests, and a true, enduring solution must be implemented. To achieve this, there are 10 assumptions that must be taken into account:

1. Israel cannot keep up a confrontation with its friends for long while its legitimacy is being eroded. This will soon begin to adversely affect the economy, based as it is on exports.

2. Without a genuine pause in settlement expansion and construction in East Jerusalem, Israel will continue to lose the support of friends and international legitimacy.

3. Israel cannot live in the shadow of a nuclear Iran. Immigration will cease, more young people will emigrate and foreign investments will diminish. An Israel that is no longer a safe home for Diaspora Jews and is not characterized by entrepreneurship and excellence means an end to the Zionist dream.

A nuclear Iran will increase the audacity of the region's extremists, threaten the moderates and lead within a few years to the acquisition of nuclear weapons by Saudi Arabia and Egypt. The regional balance of power will change to Israel's disadvantage.

4. Prime Minister Benjamin Netanyahu, in accordance with his strong beliefs on this matter, cannot allow himself to be the leader on whose watch Iran acquires nuclear weapons.

5. In the absence of "crippling sanctions" that will undermine the regime in Tehran, it is reasonable to assume that by 2011 Iran will have a nuclear bomb or two.

6. An Israeli military campaign against Iran's nuclear installations is likely to cripple that country's nuclear project for a number of years. The retaliation against Israel would be painful, but bearable.

7. U.S. President Barack Obama would find it difficult, if only for internal political reasons, to take military action against Iran and thereby open a new theater for war, in addition to Iraq and Afghanistan.

8. The acquisition of nuclear weapons by Iran during Obama's term would do him a great deal of political damage. The damage that the resulting independent Israeli strike would cause Obama - soaring gasoline prices and American casualties in retaliatory operations - would be devastating.

9. For practical reasons, in the absence of genuine sanctions, Israel will not be able to wait until the end of next winter, which means it would have to act around the congressional elections in November, thereby sealing Obama's fate as president.

10. Without international legitimacy, and with its friends mad at it, Israel would find it very difficult to act on its own.

These 10 assumptions show how complicated the situation is. Weighing them up with each other begs a single solution to the crisis with the United States: quit building. Israel should enact an open-ended freeze of settlement and outpost expansion, refrain from building new neighborhoods in East Jerusalem and stop construction for Jews in Arab neighborhoods.

The United States, independently of the UN Security Council, where sanctions would be shorn of any teeth, would implement its legislation on sanctions against Iran (an embargo on the sale of fuel and on investment in and upgrades for Iran's oil and gas industries, and a total boycott of its banking system). In so doing, it would be joined by its natural partners and important European states.

Only such an integrated solution would meet both America's and Israel's security requirements. The prime minister would find a majority in the Knesset that would rather have cooperation with the United States on this matter of survival than please the extreme right wing.

The writer is a former cabinet minister and chairman of the Center for Strategic Dialogue at Netanya Academic College.