Iran, if not stopped, will join the nuclear club, probably within two or three years. It may be stupid to try to preempt Iran; it may be even stupider not to try. But the stupidest assumption of all is that either Iran is not enriching uranium in order to obtain a weapon, or it might through negotiations or sanctions be persuaded to give up trying.

Why? In Iran’s way of thinking, nuclear-weapons capability has no downside. Diplomatic grandees who assure us that nukes are prohibitively expensive, counterproductive, a guarantee of pariah status, always disruptive to regional peace and prosperity, and never popular with the public are lying, even if they wish they were not.

There is no Iranian worry over the cost. Tehran currently exports almost half a billion dollars’ worth of natural gas and oil every day. Porous sanctions and embargoes won’t stop much of that income stream in an oil-hungry world. Unlike dirt-poor nuclear Pakistan and North Korea, Iran has the potential not just to join the nuclear club, but to do so in a big way, with hundreds of expensive bombs and delivery systems. When we speak of a nuclear Iran, we mean not something like North Korea’s five or six nukes of dubious reliability, but an entire petrodollar-fed strategic arsenal. A nuclear Iran will some day be analogous to China or India, not North Korea.

Who would be able to deter a bellicose nuclear Iran? Pakistan is deterred by its archenemy, the far larger India. Tiny North Korea is corralled by China, which enjoys the mischief Pyongyang’s few nukes cause the West — but only up to the point of not causing too much trouble in its own neighborhood.

But when it comes to deterring Iran, nuclear Israel is tiny — and is ostracized by most of the world. America is growing tired of its role as Middle East watchdog, and until recently President Obama was begging the Iranians for a new “reset” relationship. The rival Sunni Gulf sheikdoms are not known for their martial prowess. Would France step up to warn nuclear Iran not to point its missiles at Berlin? Would the EU band together to fund missile defense?

Once a rogue regime has the bomb, it seems immune from foreign decapitation. We snubbed Pakistan for its bomb and then relented and turned the dollar spigot back on. We fought two wars against Iraq only because Saddam Hussein’s nuclear-enrichment plant had been blown up earlier by the Israelis. Poor Bashar Assad should have dug his cave first, and built his nuclear plant second. Libyan dictator Moammar Qaddafi’s chief mistake was not seeking to enrich uranium, but surrendering his facilities before he got a bomb and, with it, immunity from the sort of NATO bombing campaign that removed him from power — and from this world. Had he got his centrifuges up and running safely underground, Qaddafi could have playacted his way to all sorts of concessions from Europe, as he ranted one day about taking out Rome, the next day about supplying freedom fighters with the wherewithal to neutralize Israel.

In the past, only Israel has prevented a country — first Iraq, then Syria — from going nuclear. But Iran — which tried and failed to take out Saddam’s reactor — is far larger, more distant from Israel, and more dangerous than was either Iraq or Syria.

Tehran for now bets that Israel could not pull off such an ambitious operation, or that the United States would prevent it, or that Iran’s terrorist allies in Lebanon, Syria, the West Bank, and Gaza would answer such preemption with a hail of missiles striking Israeli cities. It has a keen interest in the election year here in the United States: If Barack Obama looks as if he will be reelected, Tehran will smile, keep mum, not want to cause him any trouble, and worry only about Israel. If the polls suggest that Obama won’t return as president, Iran will worry less about Israel and more about rushing to get a bomb constructed before the next Republican president takes office.

The Iraqi and Syrian enrichment plants were visible to the naked eye; Iran’s facilities are dispersed and hidden underground. To take out Tehran’s future weapons might take a week or two of bombing, not a single day. Iran seems to want by a wink and a nod to communicate two things about its nuclear program: (a) that it is within months of completion, and (b) that it is so well fortified as to be immune from attack. Both propositions are probably untrue, but a third assumption — who would be crazy enough to find out? — is probably not.

For all the global sermons about nonproliferation, no one tried to stop either North Korea or Pakistan — an American ally — from going nuclear. India laughed when critics deplored the fact that such an impoverished country had diverted a large portion of its limited funds to detonate a bomb in 1974. China earned new international respect when it went nuclear, even as its citizens starved.

Nukes are often hailed as proof of national prestige. The world’s arch nuclear proliferator, Dr. A. Q. Khan, is still a hero in Pakistan, perhaps more so than any of its kleptocratic heads of state. North Koreans are daily reminded how the world comes to Pyongyang’s nuclear doorstep with gifts. The theocracy in Tehran bets that for all its current unpopularity at home, a “Persian bomb” would lend the imams credibility even among their pro-Western domestic critics. The regime might reassure its citizens that it would never start a nuclear war even as it hints to Israel that it could — in hopes that Israelis, 70 years after the Holocaust, would have no desire to live with a nuclear sword of Damocles over their heads, and therefore begin leaving their country. Iran could then boast that the Shiite Persian minority wing of Islam ended Zionism in a way the Sunni Arab majority never could. How many in Iran would really object to that?

The Argentines hated their thuggish military dictator General Galtieri not because he invaded the Malvinas and thus started a needless war, or because they were at heart democracy-loving reformers, but only because he failed to hold the islands, humiliating Argentina in the process. But had Leopoldo Galtieri had even two or three nuclear warheads and a rusty missile or two, Britain might well have held off, the Falklands would have remained the Malvinas, and the old thug would have outshone the earlier dictator Juan Perón.

Rarely do intelligence services ever discover another nation’s nuclear timetable. The West was shocked when Pakistan set off a bomb in 1998. To this day, no one knows how many viable nukes North Korea — or Israel — has. Did South Africa or Israel — or both, or neither — set off a nuclear device in 1979? The United States had no idea that Iraq was close to getting a bomb in 1981 or that more than 20 years later it was far away from doing so. Iran assumes that the world has no clue whether it will test a bomb this month or next decade — and it is right.

The sad truth is that nuclear capability and feigned lunacy are a winning combo. Pakistan apparently harbored Osama bin Laden and funded the Taliban for years — while raking in billions of dollars in American foreign aid. North Korea periodically provokes South Korea and threatens to go berserk with its arsenal — and by this means earns food and fuel good-behavior payoffs from the West. These shakedowns would not work if either were not nuclear. Nuclear weapons instill fear as do no other weapons, not necessarily because one bomb is always more lethal than a shower of napalm, but because in theory it easily could be. Today we talk of the horrors of Hiroshima, not the firebombing of Tokyo on March 9–10, 1945, which killed far more thousands, because the former horror required just one bomb, and the latter tens of thousands.

As long as a supposedly unhinged Iran can convince the United States that it would be gladly willing to lose Tehran in return for taking out San Francisco or Berlin — or Tel Aviv — the money will start flowing. For an affluent West, where life is pretty good, a 99 percent certainty that a nuclear threat is a bluff is not really certainty, given that that equates to a tiny outside chance that everything from the plastic surgeon’s office to the local Montessori school could go up in smoke.

No one seems to know whether any nation could — or even should — preempt the Iranian nuclear program. But everyone knows that if no one does, the Iranians will most surely get a bomb. It’s simply too good a deal for them to pass up.

— NRO contributor Victor Davis Hanson is a senior fellow at the Hoover Institution and the author most recently of The End of Sparta, a novel about ancient freedom.