The United States is looking for Iran to disclose details of its nuclear program, provide access to facilities and personnel and otherwise take concrete steps to show it is serious about complying with international demands at Thursday's landmark meeting between the countries - though American officials characterized the parley as the beginning of a long process rather than a one-time occurrence.
"What we're looking for here is a meeting that leads to a process that leads to a resolution of the concerns that we have. That process will take some time, and we're not going to make a snap judgment on Thursday," US State Department spokesman P.J. Crowley said, two days before the talks set to take place in Geneva, which he indicated could be the first of several.
"We don't think that these issues will be solved in one meeting. I don't think that we'll get the full perspective of Iran's willingness to engage in one meeting," he said.
Even so, White House officials noted they were working out implementing sanctions should these talks fail.
Though Russia and China continue to express skepticism about such sanctions, the US is looking to build greater consensus with European and other Western-friendly countries, as well as investigating further steps the US Treasury can take to dissuade international companies from dealing with Iran.
At the top of the list are persuading insurance companies underwriting Iranian shipments that they face large risks in doing so, and potentially further designating Iranian banks and individuals as entities that run counter to US legal code.
A more comprehensive petroleum embargo countenanced by Israel does not seem likely at this time.
The recent disclosure that Iran has been building a second nuclear reactor, smaller and more convenient for processing uranium for nuclear bombs, has elicited strong international reactions, but despite some harsh words, Russia and China have been pulling back from the need for further sanctions in the short term.
France gave December as the deadline for talks before further sanctions would be imposed, with the US also talking about a year-end deadline.
"It does put the Iranians more on the defensive, and it does give the administration a bit more momentum heading into the talks on Thursday," assessed one Capitol Hill aide who works on Iran policy. "It's also unfortunately clear that this was not necessarily a transformative moment for the world of diplomacy."
He added that despite the news of the secret Iranian facility, "it's not difficult to see scenarios where, by the end of this in a couple of weeks, we're back where we were - the Iranians not coming clean, the Russians and the Chinese not putting the pressure on them that we would like, and therefore the US and our friends in the world having to make a call on the sanctions process that's outside the UN Security Council."
The facility's revelation has only intensified Congress's feeling that "the only thing that is going to ultimately convince the Iranians to step back is fairly blunt pressure," according to the aide, who said that current sanctions legislation blocking Iran's ability to import refined petroleum would likely pass by the end of the year.
"There's a very strong bipartisan majority that's going to demand tougher action," he said.
Crowley said the exact configuration of Thursday's meeting would mainly be handled by EU foreign policy chief Javier Solana, who has largely handled international negotiations with Iran until now.
Like these previous talks, Thursday's conversations will take part under the rubric of the P5+1, or the US, Russia, China, England, France and Germany. The US is due to be represented by Undersecretary of State for Political Affairs William Burns. It is not clear whom Teheran will send as its representative.
Crowley did say, however, that he expected there to be one or more plenary sessions, followed by lunch and potentially further discussions.
He also indicated the US was open to the possibility of one-on-one meetings with Iran outside of the group framework.
"Any time you're together in some sort of meeting, there will be the opportunity for interaction. And we will welcome that if it happens," he said.
And as opposed to Burns's limited interaction at one previous P5+1 meeting under the George W. Bush administration last summer, Crowley said that this time, "we plan to be a full participant in the meeting and the process."
While Iran has balked at discussing the nuclear issue as part of Thursday's talks, White House spokesman Robert Gibbs stressed Tuesday that when it came to bringing up the nuclear issue, "they may not, but we will."
He said the US demands would include that the UN's International Atomic Energy Agency inspectors have "unfettered access" to the newly revealed facility, to its personnel and to its documentation.
"There's no doubt this is in violation of their own obligations, to which they're a party," he said. "If the Iranians are unwilling to discuss something that should have been reported to the IAEA years ago, I think that's quite telling."
Meanwhile, some experts are urging that the US take advantage of Iran's state preference for broader discussions to include Teheran's human rights abuses and allegations of widespread election fraud, points on which the Iranian regime is sensitive.
"With Iran, the United States should insist on discussing several issues: the nuclear program, of course, but also Iran's sponsorship of terrorism, its interference in the affairs of its neighbors and its human rights record. It is hard to see how Ahmadinejad could use such talks to relegitimize his tainted rule or reclaim the domestic initiative from dissidents challenging him," Ray Takey, a US adviser on Iran until recently, wrote in Sunday's Washington Post.
"US insistence on discussing the full array of Iranian malfeasances has the extra advantage of determining whether Teheran's proposal for comprehensive dialogue is real," he continued.
"If Iran is truly interested in escaping its pariah status, then it will swallow the bitter pill of such discussions. Conversely, if Ahmadinejad sees the negotiations only as a means of rejuvenating his image at home, he will probably reject such an agenda."