When the war in Lebanon ends, the US will have to piece together a whole new strategy for dealing with Iran – especially its nuclear program. The Israeli- Hizbullah war has boldly ratcheted up Iran's regional stature at the same time it has depleted US influence and prestige.

From the outset, the Lebanese conflict was about more than just Hizbullah. Jerusalem and Washington were quick to point the finger of blame for the conflict at Iran, and it was with Iran in mind that Israel unleashed the full force of its air power in Lebanon. The US, too, saw shock and awe in Beirut as an opportunity to convince Tehran of the West's determination to bring it into compliance on the nuclear issue.

Tehran cleary received the message and viewed the US-backed Israeli war on Hizbullah as the first stage of a war on Iran. But Tehran also used the occasion to send a message of its own to Washington. While dutifully denying a direct role in the kidnapping of Israeli soldiers, Tehran nevertheless heaped praise on Hizbullah, hoping that its engagement with Israel might dampen enthusiasm for a military attack on Iran. To further drive this point home, Hizbullah surprised Israel and the US by successfully testing a number of Iranian-made advanced weapons systems.

Iran's ties to Hizbullah run deep. It was Iranian clerics and Revolutionary Guards commanders who first organized Hizbullah in the 1980s. Since then, Tehran has bankrolled and armed Hizbullah's war machine. Many among the current leadership of Iran's Revolutionary Guards have served tours of duty at Hizbullah's headquarters in the Bekaa Valley in Lebanon. Over the past two decades, Hizbullah has evolved into a Lebanese political force, but it continues to rely on Iranian support to sustain its military capabilities.

Average Iranians resent their government's generous support for Hizbullah when unemployment and poverty plague the Iranian economy, and many bristle at the risk that support for Hizbullah carries for Iran. But Iran's leaders see Hizbullah as an ally and an asset. Hizbullah is a fruit of the Iranian revolution – the only time its seed found fertile soil outside Iran. Tehran cannot back away from Hizbullah without acknowledging that the revolution is over. Iran's hard-line leaders, looking to rekindle revolutionary fervor at home, see their own values reflected in Hizbullah.

Nor will Tehran easily give up on a pro- Iranian force in the heart of the Arab world and an important instrument in confronting Israel and the US. Tehran has basked in Hizbullah's new-found glory, taking credit for a popular military adventure that has greatly weakened Iran's traditional regional rivals – Jordan, Egypt, and Saudi Arabia.

Iran had hoped that its cooperation with the US in rebuilding a post-Taliban Afghanistan would lead to an opening in the relations between the two countries. But Washington was not keen to build on that initiative. It refused to engage Iran over the future of Iraq and instead focused its energies on containing Iranian influence in the Persian Gulf and rolling back Iran's nuclear program.

In the Lebanese conflict, Iran has found an opportunity to underscore its regional importance. The Iran-Hizbullah axis has hijacked the Palestinian cause and redefined the Arab-Israeli conflict. Neither criticism by Arab governments nor fatwas (religious edicts) by radical Sunni clerics have slowed down Hizbullah's and Iran's rising stock.

As the US looks for a way out of the crisis, it is increasingly evident that it is Iran's and not Washington's traditional allies in the region that hold the key to solving the crisis, and Tehran hopes that Washington will come to realize that without Iranian cooperation it cannot ensure regional stability.

With a population of close to 70 million, more than 70 percent of which is literate, a vibrant culture, and a geographic spread from Central Asia and the Caucasus to the Persian Gulf, Iran is today a rising power in the Middle East. Its large market, economic output, industrial potential, and vast oil and natural gas reserves make it central to American geostrategic and energy interests. Over the past two decades, Tehran has nurtured cultural, economic, and political ties with various regional forces, most notably the Shiites of Iraq. These ties confirm Iran's regional status, just as they make it more difficult for the US to bring stability to the arc stretching from Afghanistan to Lebanon without Iran.

In the coming months, Washington will have to look for ways to deal with a bullish Iran. A policy of isolation and intimidation will no longer yield results and will serve to further destabilize the Middle East. Hizbullah's tenacious resistance has moreover devalued military power as a deterrent. The war has not only failed to subdue Hizbullah militarily, but has made it politically stronger. US objectives and interests would be better served by giving Iran a vested interest in stability. That means including Iran in a new regional security framework. The US should continue to demand that Iran curb its nuclear activities, abandon support of terrorism, and respect the democratic aspirations of Iranians. The difference would be that with regime change no longer a threat, Iran will be more likely to find reasons to change its course.

• Vali Nasr teaches at the Naval Postgraduate School in Monterey and is adjunct senior fellow at the Council on Foreign Relations. He recently authored "The Shia Revival: How Conflicts within Islam Will Shape the Future."