Assume that Barack Obama is elected U.S. president this fall and makes good on his promise to negotiate with Iran without preconditions. How will Tehran respond? Recent interviews I've held with three authoritative Iranians suggest that Tehran will have preconditions of its own. Before coming to the table, these Iranians say, the United States would first have to end its "hostile policies" toward their country. The most important step pushed by all three is one already promised by Obama: setting a timetable for the complete withdrawal of U.S. combat forces from Iraq. Other moves, however—like ending economic sanctions—would conflict with Obama's campaign pledges and be even more controversial in Washington.

"Signals have come to us about negotiations before [Obama] is in the White House," I was told by Alaeddin Boroujerdi, chairman of the powerful Foreign Affairs and Defense Subcommission of Iran's Parliament and a close ally of President Mahmoud Ahmadinejad. "They have sent messages through friendly ambassadors that they are willing to talk to us." But "the ball is in [Washington's] court," he emphasized. "It is the United States that severed the connection with us, and the manner in which relations are restored should reflect that."

To create a "real change in the atmosphere," he said, Obama should halt ongoing CIA efforts to overthrow the Islamic republic, release Iranian assets frozen in U.S. banks since the 1979 hostage crisis, end banking sanctions and resume sales of civilian aircraft. That's a long list, but Boroujerdi implied that any one of these measures, plus an Iraq timetable, would be enough to get a dialogue started.

The importance of an Iraq withdrawal plan was also emphasized by Alireza Sheikhattar, first deputy foreign minister. "Whether it's three months or eight months or longer," he said, the important thing is that the United States show "a serious intention" to gradually leave Iraq. Asked whether any U.S. forces could remain there, Sheikhattar replied, "Yes, some could stay to help with training Iraqi forces." But he drew the line at any U.S. moves to make Iraq "a platform for harming the security of Iran and other neighbors."

Sheikhattar emphasized the fact that the United States currently controls Iraq's airspace, which he said "upsets" Iraqi Prime Minister Nuri al-Maliki. "The Iraqis should have a real Air Force," Sheikhattar declared. "Why are they prohibited from having more than token aircraft? They are not poor. They can purchase fighters and have their own aircraft for both internal and external security." Wouldn't this pose a security threat to Iran? I asked. Not if Iraq has a sovereign, democratic government, he said, "because there is an absolute majority [there] in favor of Iran."

Asked about Obama, Hossein Shariatmadiari, editor of the hard-line newspaper Kayhan, was reticent, observing that "anyone replacing Bush will be an improvement. I won't rule out that Obama does want a new approach to Iran. But we have to see whether he is genuine or is controlled by the same Zionist forces behind the curtain that have controlled Bush," he said. Even if Obama wants to talk, Shariatmadiari asked, "do we want to talk to him?"

The answer suggested by our conversations is that Iran does want to work out a modus vivendi with the United States—but will play hard-to-get.

Obama will be in a strong bargaining position if he sticks to his pledge to withdraw U.S. combat troops from Iraq over 16 months and also removes U.S. bombers from air bases there. In return, he could demand that Iran prevent the Iraqi Shiite militias it supports from harassing U.S. forces during the pullout, and help in rooting out Al Qaeda from Iraq—a goal Tehran shares with Washington.

To start a broader dialogue on the nuclear issue, Obama would have to take one crucial step sought by Iran: end CIA and Special Forces support for insurgents seeking to overthrow the Islamic republic, especially Kurdish separatists and the Iraq-based Mujahedin-e Khalq. This move wouldn't need to be publicly announced, however, and would thus have a low domestic political cost for Obama.

Boroujerdi, the parliamentary foreign-policy chief, said that if Washington accepted Iran's right to continue uranium enrichment for peaceful purposes, the rest of the nuclear issue would be "negotiable." "We understand and accept that the red line would be the development of a nuclear weapon," he said.

Ending the Bush administration's regime-change policy toward Iran is probably key to holding productive nuclear negotiations and would be an acceptable price to pay. But will a President Obama stand up to entrenched forces in the Pentagon, the CIA and allied intelligence services that are already engaged in covert action against Iran? That won't be easy; the next U.S. president will face tough adversaries in Washington as well as Tehran.