America's new president has begun to influence the course of events abroad even before moving into the White House. Mr. Obama is already shaping the actions of governments that are now deciding how to deal with this new phenomenon of a popular American leader who promises change rather than confrontation, and who asks for dialogue rather than insisting you are either for us or against us. Even in the Middle East, where hatreds run deep and old quarrels die hard, you can see the “Obama effect.” Especially in Iran.

We saw one of the signs when Iran's provocative President Mahmoud Ahmadinejad publicly congratulated President-elect Obama on his victory. The Iranians haven't done that since the United States broke relations with them in 1979 after Iranian students seized the U.S. embassy in Tehran and held American diplomats hostage for 444 days.

And last week, after Israel responded to Palestinian rockets by unleashing an onslaught on Gaza, a usually reliable American non-government intelligence service (Stratfor) reported that Iranian officials were urging their Hezbollah friends in Lebanon not to open a second front against Israel. The report has not been confirmed, but it makes sense that Iran would not want to be seen stirring up trouble before it has a chance to see whether Obama really means to improve relations.

Both countries have been at each other for 30 years, maneuvering for advantage and probing each other's weaknesses. The United States provided covert help to Saddam Hussein when Iraq invaded Iran in 1980. It has used economic sanctions and threats of military action in an effort to force Iran to stop its uranium enrichment program. Iran has pushed back by using its followers in the Middle East to work against American interests. In 2006 it helped arm and train the Hezbollah militia that launched a costly rocket war against Israel. That makes it all the more remarkable that Iran may now be urging Hezbollah to cool it.

Every American government since the Reagan administration has failed to find a way to work with Iran, even on the occasions when Iran was apparently ready to make a deal. After 9/11, Iran gave the U.S. quiet help in combating their mutual enemy in Afghanistan, the Taliban. The Bush administration responded by labelling Iran a member of the “Axis of Evil.” And shortly after the United States invaded Iraq, Iranian officials secretly sent a letter to Washington offering a grand bargain in which Iran would accept tighter controls on its nuclear program, stop supporting armed groups in the Middle East and even accept the two-state solution to the Israeli-Palestinian conflict. In return Iran wanted an end to American hostility and recognition that Iran has a legitimate role in the region. The White House did not bother to respond, apparently because it saw the letter as a sign of Iranian weakness.

In the past few years, another opportunity for cooperation has opened up in Baghdad. Both the United States and Iran have an interest in insuring that Iraq has a stable government that will not be a threat to its neighbors. Although the Iranians – or at least certain factions in Iran – have been providing help to friendly factions in Iraq, they have largely refrained from destabilizing the American-backed central government. That has led to behind-the-scenes talks between the U.S. and Iran, and in the past year, public meetings between Iranian and American officials. The talks have so far produced few results, perhaps because the Iranians think they could strike a better deal with the next American administration.

Iranians are keenly interested in the new American president, although they are sceptical about how much Mr. Obama can actually change American policy toward Iran. One Iranian told me he believes America's basic national interests will remain the same, but he hopes to see greater openness to dialogue in Washington.

The Iranians have a democracy of sorts and will be holding a presidential election this spring. President Ahmadinejad's popularity is weakening, and it looks as if he may be defeated. That could open up interesting possibilities if he is followed by a more pragmatic and less dogmatic successor. As the Israelis once said when they buried the axe with Egypt, it takes two to tango.