There was a startling poll on Iran last week. Many top Iranian analysts have long believed Tehran's nuclear ambitions will, more likely than not, lead to a military confrontation. What's new, Americans now agree. Cynicism is taking hold.

Americans were asked in a Fox News poll whether: "Iran can be stopped from working on a nuclear weapons program without the use of military force, or will the U.S. eventually need to take military action to stop Iran from getting nuclear weapons?"

Six in 10 Americans believe "military action will be necessary." They were not stating this view as passive observers. The same portion of Americans said they "support" the U.S. taking military action to "keep Iran from getting nuclear weapons." A majority of Independents, Democrats and Republicans came to both stark conclusions. This was one poll. But it indicates Iran cannot count on American war fatigue.

Seven in 10 Americans want Barack Obama to be tougher on Iran. Three-quarters of Americans are also "worried" about Iran developing a nuclear bomb. By comparison, not even half of the public is worried about an impending terrorist attack or a U.S. swine flu epidemic.

The public does not want immediate military action. CBS News/New York Times polling consistently finds that six in 10 Americans believe diplomacy remains the right track.

The right track, it seems, for now. Americans appear to believe diplomacy will eventually be the wrong track--providing Iran stays its nuclear course.

The Obama administration grasps--or maintains--this skepticism. Iran has a "finite period" to resolve the nuclear conflict, warned Susan Rice, the US ambassador to the UN, Sunday on "Meet the Press." "We're not interested in talking for talking's sake," she added.

France is firmer. Last week, French President Nicolas Sarkozy said that the period for talks should expire in three months. American hawks are more in line with the French than their own president. Times have changed, indeed.

Iran is the mirror of Iraq. The bugle charge is not ours. Obama is the good cop. The French are playing bad cop. And Britain's Gordon Brown apparently leans more French than American.

Obama will not subscribe to a strict deadline. He wants breathing room. Obama's team is emphasizing the most promising aspects of its new "engagement" policy. National Security Adviser Jim Jones said Sunday that last week's Iran talks demonstrated that Tehran was "willing to come to the table."

Jones also saw "very significant" signals from Iran. One, Iran's pledge to allow some inspections. Two, Tehran will potentially send nuclear material to Russia.

Yet this is Iran. Its modern history undermines Pollyannaish expectations. Iran has attempted to keep at least two nuclear facilities secret this decade. Before the United States was in Iraq or Afghanistan, Iran was after the bomb. Even Iranian moderates support the nuclear program. They too have seen how the bomb secured North Korea and Pakistan.

Slate's Fred Kaplan poses a provocative question: is Iran's engagement in talks "good news or bad?"

"Is it the prelude to serious measures that impede Iran from converting its nuclear program to a nuclear-weapons program? Or are the Iranians just stringing us along," Kaplan wrote, "while Iran continues to work secretly toward building atomic bombs? One needn't be paranoid or a neocon to suspect the latter."

The Iranians have moved away from intransigence. And that's good. But those small steps may stay small. This may be North Korea like diplomatic delay. Iran can therefore continue to split world powers. The Chinese and Russians have what they desire, no new cause to get tough.

Obama may soon need to get tough and offer a "strict deadline." That deadline would only succeed if serious. On the other side of diplomatic failure would have to be the assurance of severe sanctions or the possibility of force.

High-level experts at the UN nuclear agency now believe Iran has "sufficient information to be able to design and produce a workable" atom bomb, according to The New York Times.

The Iranian nuclear issue is a matter of construction, not architecture. And construction can be delayed with force. Entrances to underground facilities can be bombed. Delay may mean a few years. But that may be enough for now. Soon the Iran nuclear issue may only concern the best of bad options.

There is still time for talks. "I am actually for negotiations [with Iran] though I don't think they'll get anywhere," European intellectual Timothy Garton Ash said on CNN.

Eventually, talks may get us where we do not want to go. Not only Israelis are anxious. CNN polling finds that 43 percent of Americans view Iran as a "very serious" threat; 36 percent say "moderately serious." Only 13 percent term Iran a "slight threat." Less say "no threat."

Obama must prove talks can also defeat threats. Obama has to convince the Iranians to stick with diplomacy. He must also convince his public that diplomacy can work.

Obama ran for the presidency on soft power. Now he has to prove that soft power is power. He has to prove his public wrong. They want talks. But they expect Iran to come to force.

The most famous line about warfare is from Carl von Clausewitz: "War is a continuation of diplomacy using other means." Despite some progress on Iran, those "other means" appear more likely. And it's not only hawks who now think so. It's the wider American public. That means expecting the worst is, perhaps, no longer cynical, but realistic.