Yuval Steinitz is Israel’s minister of intelligence.

A final deal that allows Iran to retain centrifuges for uranium enrichment ultimately would allow the development of nuclear weapons in Iran, encourage a Sunni-Shiite arms race in the Middle East and weaken counterproliferation efforts worldwide.

Iran already possesses ballistic missiles suited to carry nuclear warheads and advanced knowledge of weaponization. Given that the production of fissile material — whether by enriching uranium in centrifuges or extracting plutonium from nuclear reactors — is the principal stage in the process of making a nuclear weapon, acquiescing to Iranian enrichment is tantamount to legitimizing Iran’s status on the nuclear threshold.

Proposals for the final agreement to restrict the number of centrifuges are almost irrelevant. Even if Iran were forced to reduce its number of centrifuges to only 3,000, its stockpile of uranium enriched to 3.5 percent would allow the production of enough fissile material for a nuclear bomb within six months. If forced to start from scratch with 3,000 centrifuges, Iran could still produce enough fissile material to make a nuclear weapon within one year.

The chances of Iran developing the bomb as a “threshold country” are considerable: North Korea did so after signing a similar deal in 2007. Becoming a nuclear power was the ayatollahs’ initial objective and the reason Tehran invested around $50 billion in this project. Yes, there are other countries on the nuclear threshold, but unlike Germany and Japan, Iran is unlikely to maintain its threshold status.

The ayatollahs’ regime poses a threat to its Sunni neighbors. Tehran calls for the annihilation of the Jewish state and sponsors terrorist groups such as Hezbollah and Islamic Jihad, all of which sparks fear in other countries. Sooner or later, Tehran’s anxiety over potential retaliatory actions against its regime, including its nuclear project, would increase pressures within Iran to dash toward a fait accompli nuclear weapon.

As for the Sunni-Shiite arms race, the critical reaction to an international agreement would be not in Washington but in Cairo, Ankara and Riyadh. Even if the Western powers express confidence in Iran’s commitment and pledge a vigorous economic and military response to any Iranian violation, regional players will render their own judgments.

Iranian President Hassan Rouhani’s “charm offensive” has had a dramatic effect in the West, but no one in the Middle East buys Iran’s projection of pacifism. Indeed, Tehran’s direct involvement in Sunni-Shiite carnage in Syria, Lebanon and Iraq has sharpened its image. Iran’s breakout capability will be pivotal in regional assessments, with most governments likely to conclude that if the deal leaves Iran only a year or two away from the bomb Tehran ultimately will go nuclear.

Any deal that legitimizes Iran as an unpunished, sanctions-free country on the nuclear threshold might spark a nuclear arms race in the region, as Saudi Arabia has hinted. Some Sunni states might seek to develop the bomb in a bid to achieve parity with Iran or to ensure their ability to join the nuclear club if Tehran does. Paradoxically, such an arms race might provide Tehran the ultimate excuse to produce the bomb: to keep pace with the rivals its own actions drove to go nuclear.

Even if Iran kept its commitment to avoid the bomb, allowing it to retain centrifuges could have grave global implications. Should the final compromise include de facto recognition of Iran’s “right to enrich,” the international community would find it difficult to insist later that other problematic regimes concede that “right.”

Unfortunately, the interim agreement has already linked Iran’s hypothetical future enrichment to its civilian “practical needs.” Practical needs is interpreted mainly as enrichment needed to fuel nuclear power stations. Such a civilian purpose demands more centrifuges than are in Iran’s inventory. In other words, it seems to allow for even more centrifuges than are militarily needed for the annual production of several nuclear bombs.

More than 20 countries produce electricity in nuclear reactors, and dozens more are planning to do so. If Iran were ultimately allowed to enrich, how would the United States justify its demand that, say, Egypt, Jordan or South Korea eschew uranium enrichment for peaceful civilian purposes? How would U.S. officials argue that what the deal concedes to the ayatollahs’ regime, after a decade of flagrant violations of six U.N. Security Council resolutions and their commitments under the Non-Proliferation Treaty, is forbidden for more responsible countries? How could the United States cast greater legitimacy on the previously clandestine centrifuge facilities in Qom and Natanz than on those that would be aboveboard from the outset?

Inevitably, multiple countries, including some rogue states, would insist on their own enrichment facilities. With centrifuges equally capable of enriching uranium for nuclear energy or nuclear bombs, such a deal might generate many new threshold states.

Under such circumstances, local disputes or changes in government eventually would push some countries across the threshold. Ironically, a deal intended to prevent the nuclear armament of one dangerous country, Iran, could plant the seeds for the wholesale sprouting of many nuclear powers.