Last week, someone at a dinner party asked me if I'd heard that Iran was going to destroy Israel on Aug. 22.

The question was provoked by an unbelievable Aug. 8 op-ed in the Wall Street Journal written by the Mideast historian Bernard Lewis. He speculated that Iran might want to hasten the Shiite version of Armageddon by ending the Jewish state on that date, because that day coincided with the Islamic anniversary of the Prophet Muhammad's night flight from Jerusalem to heaven.

Never mind that Iran is years away from having a nuclear weapon and has no present means to destroy Israel, even should Iranian leaders want to commit certain suicide. Iran and the revolting rhetoric of its president, Mahmoud Ahmadinejad, provoke eminent historians — and U.S. policymakers — to lose their grip.

Prepare for more such emotionalism in the aftermath of the war between Israel and Hezbollah, and in the wake of Iran's rejection this week of U.S. and European terms for negotiations on its nuclear program. But such overreaction obscures the only plausible U.S. policy path to limiting Iran's nuclear program: The Bush administration must make Iran an offer it can't refuse.

The negotiating process with Iran has been haunted from the start by a basic contradiction in American policy. The White House can't decide what is its highest priority: changing Iranian behavior or changing the regime.

The Bush team has been unwilling to offer the one carrot that could make Iran reconsider its actions: assurance that America will not undermine or attack the Iranian regime. In return, Iran would have to freeze its nuclear program and stop destabilizing the region — and halt its aggressive posturing toward Israel.

The White House has steadfastly refused to offer any such deal.

In 2003, when America was newly triumphant from the Afghan war, Iran conveyed an interest in a "grand bargain" that included acceptance of a two-state solution to the problem of Israel and the Palestinian territories. The White House wasn't interested.

In spring 2006, Tehran sent numerous signals that it wanted talks, including the first public endorsement of the idea by Iran's supreme leader, Ayatollah Khamenei. (In Iran's system, Khamenei, not Ahmadinejad, controls foreign and nuclear policy.)

When I was in Iran in May, Iranian officials bombarded me with the message that America needed their country's cooperation for stability in the Middle East. The intensity of the message convinced me that America had bargaining chips that Iranian officials badly wanted — recognition of their regime and acceptance of their economic and political role in the region.

Iran's interest in talks waned in late spring, when the West's negotiating proposal offered no hint of American security pledges. Iran was required to suspend all nuclear enrichment activities as a precondition to talks. In return, Iran would get economic and technological benefits.

But the administration constantly dropped hints about the need for a new regime in Tehran. U.S. support for Israel's bombing campaign in Lebanon looked like a dry run for a possible U.S. attack on Iran. So why be surprised that Iran stirs up problems in Iraq or arms its Lebanese proxy, Hezbollah?

None of the options the White House faces on Iran is a good one. If Iran fails to give a clear answer on the European-U.S. proposal by Thursday, the administration will press for U.N. economic sanctions — which won't stop Iran's nuclear program.

As for the military option, a U.S. bombing strike on Iranian nuclear facilities won't halt the program either. Many of the sites are underground, and we suspect that some are in secret locations. A strike would strengthen Iran's regime, accelerate its nuclear program and ensure that Iran's Shiite allies in Iraq turned on U.S. troops.

Iran's top nuclear negotiator, Ali Larijani, said Tuesday that Tehran was ready to enter "serious negotiations," but he left opaque what that meant. Given the options, why not test Iran's bona fides? Iran's position in the region is likely to get stronger the longer we dally, but the White House has cards to play if it is willing to use them.

Why not try?

Trudy Rubin is a columnist and editorial-board member for the Philadelphia Inquirer. Reach her at trubin@phillynews.com.