No one said that reaching at an agreement with the Iranians over their controversial nuclear program would be easy. But after yet another failed round of negotiations between the Islamic republic and the five permanent members of the United Nations Security Council plus Germany over Tehran’s nuclear ambitions, officials on both sides must begin to wonder whether a deal can ever be done.

Iran and the P5+1 have been forthright enough to sit around the same table to lay out their viewpoints and demands yet the optimism that persisted after the first meeting in Istanbul last April, which delivered no agreement whatsoever, has all but dissipated as both sides hard up their positions.

Negotiations between the Iranians and world powers have long come to resemble the old game of verbal bellicosity, a toning down of heated rhetoric, actual meetings leading to a small sense of positivity, only to collapse when the nuts and bolts of the issue are discussed. The conclusion of the talks in Moscow this week carried with it the same qualities, namely inflexibility and an absolute lack of trust which have ruined previous discussions over the Iranian nuclear question.

The discussions have revolved around a goal that is as unattainable in the current environment as it is idealistic — a cessation of Iran’s enrichment of uranium at high levels and the establishment of a robust, consistent and verifiable United Nations-sponsored inspections regime inside of that country.

For Iran, the talks are geared to accomplish the equally important objective of retaining the right to enrich uranium for peaceful purposes while lifting all of the economic sanctions against the country.

The deadlock can only be breached if one side is able to promise the other a deal that is too tempting to resist.

For a time, that conundrum looked like it could be unraveled. After the first meeting in Turkey, the Iranians were pleasantly surprised of the warm atmosphere they received during the two days of dialogue. Catherine Ashton, the European Union’s foreign policy chief, was equally surprised that the Iranians seemed willing to engage seriously on their nuclear program. But as all honeymoons do, the smiles and good times fizzled out after the teams went back to their home capitals. Iranian government officials decided to escalate their rhetoric about defending the nuclear program at all costs while the United States Congress pushed through even more sanctions on Tehran in a signal that the country was preparing to unleash additional financial pressure if diplomacy failed.

Nearly two months since, the talks that have been billed as perhaps the last chance to resolve the conflict peacefully are once again on thin ice.

The challenge for the Obama Administration is to keep the talks alive and the diplomatic option open with it as well as to forestall any Israeli murmuring about an unilateral strike on Iran’s nuclear sites. If President Barack Obama is sincerely interested in arriving at an agreement, he must be open to providing the Iranians with more of what they are asking for.

A promise to allow american spare parts for Iranian airliners in exchange for a full suspension of enrichment at the 20 percent level is not something that Tehran will sign up for, nor is it something that many analysts who have been watching the issue tirelessly for the past decade consider tempting enough for the Iranians to give up important concessions.

What exactly President Obama could do to convince the Iranians to respond positively is something that his administration will have to debate internally, mindful that any major concession will be billed by his Republican challenger Mitt Romney as a dangerous capitulation to an erstwhile American foe.

More than thirty years of adversarial relations have generated a general belief in Washington that the Iranians are too much trouble to make nice with. If the administration has any shot at breaking away from past precedent, it will need to be far more open to Iranian concerns than it is currently. The fact that this challenge comes at a time when President Obama is fighting to keep his job makes the call all the more difficult.