As Iran on Thursday celebrates the 31st anniversary of its Islamic Revolution, Americans overwhelmingly agree on one thing — the country cannot be allowed to have nuclear weapons.

At the same time, a smaller majority believes the U.S. will take military action before Iran's nuclear program gets to that point. Interestingly, however, most Americans are skeptical that such action will be successful.

These are key findings from the latest IBD/TIPP poll of 901 Americans completed on Feb. 7. The poll has a margin of error of plus or minus 3 percentage points.

The U.S. and its allies have long believed Iran is refining uranium to develop nuclear weapons on the pretext of civilian use for medical treatment and power plants. A nuclear Iran could potentially trigger an atomic arms race in the Mideast as well as threaten Israel and other U.S. allies in the region.

This month's poll showed that 80% of Americans do not want to see a nuclear Iran. That includes 77% of Democrats, 89% of Republicans and 77% of Independents.

Growing Threat

A majority (52%) believe that during the Obama administration, Iran has become a bolder and bigger threat than ever. But this view is more common among Republicans (71%) and Independents (51%) than Democrats (40%).

Americans' support of U.S. military action to stop Iran from getting nuclear weapons has ranged from 52% to 37% last March to 46% to 42% in October. This month's spread was 47%-41%. Our polls have consistently showed more support for Israel's taking the lead. This month, 53% were in favor of Israeli military action against Iran — about the same as in previous months.

In 1981, an Israeli bombing raid destroyed Iraq's French-made nuclear reactor. Israel also likely took out a Syrian reactor in 2007. The situation with Iran is somewhat different in that its nuclear facilities are spread out in secret underground locations.

Iran's clerical regime is simultaneously engaged in a domestic and an international battle. On the domestic front, millions of supporters of the opposition Green Movement are planning protests to coincide with Thursday's anniversary. They are led by Mir-Hossein Moussavi, who lost to Mahmoud Ahmadinejad in last year's bitterly contested presidential election.

The Ides Of February?

Bluster from the Iranian regime has marked the days leading up to the anniversary. On Monday, Supreme Leader Ayatollah Ali Khamenei boasted to air force officials: "The Iranian nation, with its unity and God's grace, will punch the arrogant (Western powers) on the 22nd of Bahman (Feb. 11) in a way that will leave them stunned."

It followed up Tuesday by taking the next major step in the uranium-enrichment process: starting its reactors to boost the uranium in its possession from the 3.5% level to the 20% required to fuel power plants. To fuel nuclear weapons Iran needs to enrich uranium to a level of 90% or better. According to estimates, improving to 90% from 20% would take only six months.

Americans see their country moving gingerly. Nearly three of four (73%) share the opinion that if the U.S. takes military action against Iran, it would not be in haste and would only be as a last resort when all other options fail to stop Iran from developing a nuclear weapon. This view is nearly universal and across party and ideology lines.

A majority (53%) are also confident the U.S. would take military action before it's too late.

Two-thirds (68%) of Democrats and nearly half (49%) of Independents share this view. But most Republicans (51%) are skeptical.

While the public is confident the U.S. would take careful, well-timed military action, 51% are not confident the U.S. will be able to prevent Iran from developing nuclear weapons. Only 46% are confident it would. Fully 62% of Republicans are skeptical, despite their traditionally hawkish stance on the issue. Interestingly, a large share of Independents (56%) also share this pessimistic view. On the other hand, 61% of Democrats are optimistic.

Americans do not see President Obama's handling of Iran in a positive light. Only 30% of Americans give him an A or B. Just over a third (37%) grade him a D or F. One in four give him a C.

Even Democrats, 74% of whom give the president good grades overall, are much less approving (51%) when it comes to Iran. The president does not pass muster with Independent voters. Only 20% of Independents give him good grades; another 44% give him bad grades. Republicans are the harshest with 57% giving him a D or F.

'Significant' Sanctions

In response to Iran's latest move to enrich uranium to the 20% level, Obama has warned of a "significant regime of sanctions." On Wednesday, the administration imposed new sanctions on several affiliates of Iran's Revolutionary Guard Corps, targeting one person and four companies for alleged involvement in producing and spreading weapons of mass destruction.

Overall, 44% think Obama has a good understanding of the gravity of the Iran situation. A majority of Republicans (55%) think he does not have a good understanding, while a majority (69%) of Democrats think he does. Independents' views are divided, with 38% favorable and 33% unfavorable.

• Mayur is president of TechnoMetrica Market Intelligence, which directs the IBD/TIPP Poll that was the most accurate in the last two presidential elections.

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