The Bush administration may be on the verge of getting what it has long sought: United Nations sanctions on a defiant Iran over its accelerated nuclear program. That may not be much of a victory. The UN Security Council isn't likely to approve tough sanctions anytime soon, analysts said, and Iran can easily shake off light punishments. The United States risks shattering an international coalition it fought hard to build if it plays the bully now. Perhaps emboldened by what it views as a proxy victory over the West during the month-long Israeli war with Iranian-backed Hizbullah, Teheran is testing the unity of the international front against it. Iran has so far ignored an August 31 UN deadline to stop nuclear development activities that Washington and some allies say is evidence that Iran wants to build a bomb. Iran says it wants only to develop peaceful nuclear energy, and has made its program a point of national pride. On Tuesday, Teheran presented a lengthy response to a package of Western incentives, drawn up by the five permanent UN Security Council members and Germany, to get Iran to roll back its program. Washington considered the reply overdue and insufficient. The offer came with the sweetener - a promise that the United States would join negotiations with Iran over the package if Iran first halted uranium enrichment - and the threat of sanctions if Iran failed to comply. Iran said it was prepared for "serious negotiations" but did not agree to the key condition. Enriched uranium can be used either for weapons or to produce nuclear power. "If a will is going to be imposed on us, we will be ready to pay the price for defending our rights," Mohammad Reza Bahonar, vice speaker of Iran's parliament, told the semiofficial Iranian Student News Agency on Friday. If the deadline passes without any movement, the Security Council could take up a sanctions proposal as soon as next week. The Bush administration has urged just that for more than two years, while European nations tried and failed to talk Iran out of the most troublesome aspects of its nuclear program. Although slow and frustrating, the Iran diplomacy has so far represented a qualified victory for the United States. Once deeply suspicious of US motives in Iran and put off by tough talk from Washington, European governments have largely come around to the US view that sanctions, or the threat of them, is the best strategy left. Even Russia and China, with economic and strategic reasons to side more with Iran than with the United States, reluctantly agreed to the carrot-or-stick package now on the table. Those nations hold veto power as permanent members of the Security Council and are considered Iran's best defense against harsh punishment. Now with sanctions looming, long-standing divisions and anxieties among the partners Washington will need are coming to the fore. European nations with strong commercial ties to the major oil and energy exporter would be hurt themselves by the very sanctions on energy exports that would probably be most effective. The United States is likely to bow to the European preference for weak sanctions as a first step. That would leave the Bush administration making the best of half-measures, such as a ban on travel by Iranian officials, while pressing for tougher economic sanctions down the line. If Iran can split off Russia or China now, there may be no sanctions at all. Iranian-born author and Middle East scholar Trita Parsi interprets Iran's ambiguous response this week as a bid to blur the bright lines of the UN demand, perhaps by offering a very brief suspension of enrichment. He thinks European nations may be tempted. "Sanctions with teeth tend to bite back," Parsi said, and European leaders know their publics don't think the Iranian nuclear threat is worth economic hardship at home. From Teheran's perspective, there is good reason to stall, said Council on Foreign Relations fellow Michael Levi. "If their strategy was to divide the Security Council it seems to be working," Levi said, citing Friday's remarks from the Russian Vice Premier Sergei Ivanov that talk of sanctions is premature. Meanwhile small nations that can vote, but not veto at the Security Council are in an uproar over perceived US bias toward Israel in the recent war with Hizbullah militants. It is unclear how much opposition those nations could raise to a US-backed sanctions plan. The United States should probably take what it can get at the Security Council for now, Levi said. He said mild sanctions are better than no sanctions, if only as a signal to Iran that the United States and its partners won't back down from a fight. "There is no credible threat of sanctions if no one is willing to take even the smallest first step," Levi said. "Without even minor steps right now, Iran has essentially no reason to comply with UN demands."