So, if negotiations occur — a big if — what can we expect?

For that answer, it's worth remembering the scorpion scene in "The Appaloosa," an otherwise forgettable Western from 1966. For excruciating minutes, the hero, played by Marlon Brando, arm-wrestled the talkative, confident villain who had tied a scorpion to the top of the table. In the same manner, we will go back and forth with the Iranians, each sounding off until one side's arm weakens, hits the table and gets stung.

The Iranians know from recent history that their acquisition of a bomb would have little downside. They figure that had the Israelis not destroyed Saddam Hussein's nuclear reactor at Osirak in 1981, Kuwait would still be the 19th province of Saddam's untouchable Iraq.

North Korea is the model of a rogue nuclear state. It thumbs its nose at the international community, but over the years has still earned billions in aid money (essentially bribes) from the U.S., South Korea and China. Only the bomb allows an otherwise failed, murderous regime in Pyongyang to achieve status with nearby democracies in Taiwan, Japan and South Korea.

Then there's Pakistan, a so-called American ally that, thanks in large part to its nuclear-weapon capability, can shrug off our pleas to ferret out Osama bin Laden and Ayman al-Zawahiri.

With a few nuclear missiles, Iran knows it could dictate the strategic landscape of the Persian Gulf — bullying Gulf sheikdoms over border disputes and petroleum output and claiming the forefront in the Islamist struggle against Israel. A "Persian bomb" wins national prestige and quells dissidents at home, while ensuring enough unpredictability to keep oil prices sky-high.

For those reasons, a nuclear Iran would be a Western nightmare. Periodically, we would have to reassure states within missile range of Tehran, from Germany to Saudi Arabia, that the United States is willing to go to war to keep them safe — and thus they need not go nuclear themselves.

Given these circumstances, why would the U.S. and Iran ever face off at the negotiating table?

Because each thinks the breathing space works in its own favor. Iran views talking with the U.S. as a reprieve from the threat of a military strike — or at least American-inspired embargoes and sanctions at the U.N. If the mullahs can sweet-talk the Americans while secretly pressing ahead to get the bomb, they might get home free yet. Indeed, in 2008, with the "cowboy" George Bush out of office, the next U.S. president might deal with Iran's nuclear aspirations as America did with Pakistan's in the 1990s — stern lectures but little action.

The U.S. wants more time before a showdown as well so that we can make a better case to the international community that the oil-exporting theocracy really wants more than peaceful nuclear power.

Time also provides a window to learn exactly where Iran is on the road to full uranium enrichment, and perhaps even to allow Iranian dissidents to strengthen, or nearby democratic Iraq to stabilize, or our own military to refine its 11th-hour plans.

Such a breather would be reminiscent of the Paris Peace Talks with the North Vietnamese, from 1968 to 1973, in which each side thought protracted negotiations would favor its cause. The U.S. always insisted on a free autonomous South; the North never gave up its dream of a unified communist Vietnam.

In that impasse, we thought talking and periodic cease-fires would buy time for the South Vietnamese to strengthen enough to resist the inevitable aggression to come. The North Vietnamese were equally convinced the U.S. public in the interval would grow ever more tired of the Vietnam "quagmire" — and then they could pounce.

After endless negotiations, the Watergate scandal and the Senate's curtailment of aid to the South, North Vietnam patiently waited for its moment and then renewed the war. By 1975, the communists had won what they could not in 1968.

Ahmadinejad surely remembers that precedent. No wonder he wants us to arm-wrestle over his nuclear scorpion.

Victor Davis Hanson is a classicist and historian at the Hoover Institution at Stanford University. Reach him at author @victorhanson.com.