It all started with our good friend, the Shah, who installed a small U.S.-supplied research reactor in 1967. Seven years later, he ordered four power reactors from Germany’s Siemens/AEG. He then proceeded to put together a complete fuel cycle from gaseous diffusion of uranium to enrichment, plus plutonium reprocessing (which is the other way to the Bomb). It was all for electricity generation, of course—in a country that was awash in oil.

In 1974, Reza Pahlavi confided to Le Monde: “Sooner than is believed,” Iran will have “a nuclear bomb.”¹ U.S. watchdogs concurred. The gargantuan power program of 23 gigawatts would be capable of churning out enough bomb-grade material for up to 700 warheads per year—a wild-eyed prediction, but grim enough to concentrate minds.

Megalomania played a role, yes. Like Persia’s ancient kings, the “Shah of Shahs” would thrust Iran to the “gates of the great civilizations.” Add almost unlimited funds from oil, the price of which had soared twelve-fold in the seventies. But also count the threats all-round: Iraq, an arch enemy, lurked next door; the Soviet Union cast its shadow southward; in the East, India had exploded its first nuclear device in 1974, and Pakistan would surely follow.

The point of this brief tale is that geography beats ideology in the state system. So after the Shah fell and the Khomeinists took over, revolutionary fervor merely compounded the logic of Reza Pahlavi’s realpolitik. It is bruited about that Ayatollah Khomeini had issued a fatwa against all things nuclear after toppling the Shah’s regime in 1979. If so, the injunction had a very short shelf-life. Iraq attacked Iran in 1980, launching the longest war in the modern Middle East, a war that may have caused a million deaths by its end in 1988.

Fatwa or not, this was the point where the servants of Allah smoothly resumed the path laid out by the godless U.S. “lackey” Reza Pahlavi. Nukes were to deter Saddam Hussein once and for all. Saddam, according to the Duelfer Report in the aftermath of the U.S. invasion in 2003, had gone for a mirror strategy, reaching for nukes to cow the Shah and then the Ayatollah. Iran was the target, not Israel.

With Saddam gone, the Khomeinists found an even better reason to accelerate their nuclear arms program. Now the purpose was to deter the Great Satan. Throwing its weight around after the demise of the Soviet Union, the United States had invaded Iraq in 1990 and Afghanistan after 9/11. To boot, Iranian nukes would intimidate the Little Satan, Israel. And as a geopolitical bonus, the nukes would also extend an umbrella over Iran’s revolutionary expansionism. First, Iran would sink roots in Iraq, a bulwark the U.S. had conveniently leveled. Then, in a pincer movement, it would supply Hezbollah in Lebanon and Hamas in Gaza to encircle Israel. Thus Tehran would buy itself a border on the Mediterranean. After 2011, the Revolutionary Guards completed the land bridge to the Levant by digging in in Syria.

Nukes deliver not only existential deterrence, but also indirect benefits for the offense. You want to expel us from the Levant, Syria and Yemen by attacking us conventionally? Or you want to topple our regime? Think again. If driven to desperation, if we have nothing to lose, we can at least inflict cosmic damage on you. And even far short of such an apocalypse, Iranian nukes will at least overawe local adversaries like Israel or Saudi Arabia.

The point is that nuclear weapons are useful. What the Shah began, Allah’s revolutionaries have been assiduously perfecting. So why ever give up such a valuable asset—one that provides both life insurance and an umbrella for domination, while also yielding a status bonus on the side?

If Donald Trump wants to make true on his warning that Iran will “never have a nuclear weapon,” he will have to go to war. Sanctions will not work, even though Iranian oil exports have dwindled to 400,000 barrels per day, as opposed to the historical average of 3 million. Iran is being cut off from the international financial system. Inflation, unemployment and shortages are soaring. Yet recall that economic warfare immiserates the people, not the regime or the military. The regime will stay on top, having eliminated every opposition group since 1979. Nazi Germany suffered the worst sanctions ever: the obliteration of its cities and industries, yet an effective revolt did not ensue. It took the Red Army conquering every square foot of Berlin before Hitler committed suicide.

Tehran suspended its nuclear program only briefly in response to pressure. After “Mission Accomplished” in April 2003, the regime must have felt truly shaken, given America’s victorious war machine next door. But soon enough, Iran’s rulers realized how vulnerable George Bush’s army was, especially once the insurgency started in November. Since then, they have learned that Obama’s and Trump’s America were almost all bark and little bite. Indeed, Trump is more likely to stop tweeting than to start a real war in the Middle East.

But a real war would be necessary in order to defang a nuclearizing Iran. Symbolically dropping a few bombs would not be enough. First, you would need to destroy the country’s air defense network and its command-and-control nodes. Second, you would have to obliterate the Iranian air and missile forces. Finally, you would have to flatten coastal batteries and sink the naval forces that threaten tanker traffic in the Gulf. And before hostilities even begin, you would want to position plenty of men and hardware to deter or defeat “asymmetric warfare,” against, say, Saudi-Arabia or Israel. (Hezbollah might rain thousands of missiles on the Jewish state.)

With all this accomplished, on to the nuclear sites—about 50 of them. Iran has acted according to the principle “hide, harden, and hoard.” Some targets the planners simply don’t know. Others, like in Fordo, are protected by 200 feet of rock. Yet others are located in Tehran or Isfahan, in large population centers implying vast civilian casualties and thus deterring attack. Finally, the target list is swelled by multiple redundancies. The task would be a hundred times more difficult than the Israeli in-and-out forays against Iraq’s Osirak reactor 1982 and Syria’s Al Kibar installation in 2007.

Having promised “no more war” in the Middle East, Trump is not likely to launch the kind of campaign needed to annihilate Iran’s vast nuclear network. Neither would Israel, despite its fearsome rhetoric. The U.S. can, but won’t; Israel, for all its clout, would want to, but can’t.

And alas, the Iranians know it.

What upside, hinted at above, can there possibly be to all of this?

What follows is speculation, though rooted in history. Recall that the Iranian program has been the longest-running of all time. It has stretched over many decades without actually producing a bomb, whereas the secret programs in Israel, India and Pakistan granted these states nuclear status in relatively short order. So for all the benefits nuclear weapons have for Tehran, there is the paradox of caution. Maybe the regime has been calculating that it’s better to have an almost-bomb than the real thing. To have everything in place delivers many of the benefits of an actual force without turning Iran into a global pariah, if not a target of destruction.

If this is the case (a big if), an argument in favor of negotiations and pressures, sanctions and incentives might follow. If these time-honored techniques fail, then take another traditional tack: alliances and containment, elements already present in the Middle East. Behold the strategic realignment that has pushed Israel and the Sunni states into an unwritten coalition. Finally, add to the old some very new methods, like the type of offensive cyberwar practiced by the U.S. and Israel. The best-known in a large bag of tricks is the “Stuxnet” virus that disabled thousands of Iranian centrifuges.

But just to trumpet “no nukes, never” in the style of Donald Trump—that will not work. Short of massive war, the best hope rests in an array of policies like those just limned that will persuade the Iranians not to cross the threshold from an almost-nuclear power to a real one.

To disarm them requires the kind of war Trump will not unleash—not now, not in his next term.