May 20, 2008  -- Barack Obama's original answer seemed crystal clear: last July, asked whether he would meet with the "leaders" of Iran, Syria, Venezuela, Cuba, and North Korea "without precondition," during his first year as president, he quickly answered yes.

"I would," Obama, D-Ill., said at the CNN/YouTube debate. "And the reason is this: that the notion that somehow not talking to countries is punishment to them -- which has been the guiding diplomatic principle of this administration -- is ridiculous."

Obama has not renounced his commitment to meet directly with the leaders of rogue nations, including Iran. But in recent weeks, his top aides and advisers have sought to add caveats to his promise, as Sen. John McCain, R-Ariz., has made Obama's debate answer a central campaign issue.

Obama Camp Offers Nuanced Approach

The Obama campaign is now offering a more nuanced approach that would not necessarily include a presidential meeting with Iranian President Mahmoud Ahmadinejad -- and that stresses diplomatic work that would take place before any such meetings take place.

Asked about Obama's original statement Tuesday morning on CNN, former Sen. Tom Daschle, D-S.D., a top Obama adviser and supporter, said top-level meetings would not be immediate -- and would not happen without preliminary extensive diplomatic work.

"I would not say that we would meet unconditionally," said Daschle. "Of course, there are conditions that we [would] involve in preparation in getting ready for the diplomacy. ... 'Without precondition' simply means we wouldn't put obstacles in the way of discussing the differences between us. That's really what they're saying, what Barack is saying."

Susan Rice, a top Obama foreign policy adviser, said Monday that Obama's meetings with Iranian leaders might not include Ahmadinejad.

"He said he'd meet with the appropriate Iranian leaders. He hasn't named who that leader will be," Rice said on CNN. "It would be the appropriate Iranian leadership at the appropriate time -- not necessarily Ahmadinejad."

Candidate Defends Position

Obama told ABC News' Jake Tapper in an interview Tuesday that he sees no contradiction in the statements, explaining that he has always said that lower-level diplomatic contacts would lay the groundwork for a presidential meeting.

"I have to say I completely disagree that people have been walking back from anything," Obama said. "They may be correcting the characterizations or distortions of John McCain or others of what I said. What I said was I would meet with our adversaries, including Iran, including Venezuela, including Cuba, including North Korea, without preconditions, but that does not mean without preparation."

On CNN, Tuesday, Obama echoed Rice, saying he may not meet with Ahmadinejad.

"I think this obsession with Ahmadinejad is an example of us losing track of what's important," he said. "I would be willing to meet with Iranian leaders if we had done sufficient preparations for that meeting.

"Whether Ahmadinejad is the right person to meet with right now, we don't even know how much power he is going to have a year from now," he added. "He is not the most powerful person in Iran. And my expectation, obviously, would be to meet with those people who can actually make decisions in terms of actually having them stand down on nuclear weapons or stopping funding [of] Hamas or Hezbollah or meddling in the affairs of Iraq."

Iran's highest-ranking political leader isn't the president -- it's the supreme leader, who is selected by the country's religious leadership.

Obama began making clear that he would engage in "preparations" before a meeting starting shortly after the July debate, after Sen. Hillary Rodham Clinton blasted his answer as displaying naiveté about the diplomatic process.

Still, as recently as September, he reiterated his promise to meet with Ahmadinejad himself. Asked about that commitment in the midst of a firestorm over Columbia University's decision to invite the Iranian president to speak, Obama indicated that he stood by it.

"Nothing's changed with respect to my belief that strong countries and strong presidents talk to their enemies and talk to their adversaries," Obama said. "I find many of President Ahmadinejad's statements odious and I've said that repeatedly. And I think that we have to recognize that there are a lot of rogue nations in the world that don't have American interests at heart. But what I also believe is that, as John F. Kennedy said, we should never negotiate out of fear but we should never fear to negotiate."

Last week, in South Dakota, Obama sought to explain what he meant at last July's debate when he agreed to meetings "without preconditions."

"Preconditions, as it applies to a country like Iran, for example, was a term of art because this administration has been very clear that it will not have direct negotiations with Iran until Iran has met preconditions that are, essentially, what Iran views and many other observers would view as the subject of the negotiations," Obama told reporters.

"The point is that I would not refuse to meet until they agree to every position that we want, but that doesn't mean that we would not have preparation," he continued. "The preparation would involve starting with low level, lower-level diplomatic contacts, having our diplomatic core work through with Iranian counterparts -- an agenda. But what I have said is that, at some point, I would be willing to meet."

McCain's Sharp Critique

McCain has focused intensely on Obama's answer at the debate last summer, while ignoring his subsequent attempts to clarify his position.

"Sen. Obama wants to sit down with [Ahmadinejad] unconditionally, face to face," McCain told reporters in Miami, Tuesday. "It enhances Ahmadinejad. What are they going to talk about, the destruction of Israel?"

While Obama has said he has been consistent throughout the past year, even some Democrats detect an evolving position.

"This is a fellow who, I think, shorthanded an answer that, in fact, was the wrong answer, in my view, saying, 'I would, within the first year' -- it implied he'd personally sit down with anybody who wanted to sit down with him," Sen. Joe Biden, D-Del., a former presidential candidate, who is now neutral in the race, said on ABC's "This Week" on Sunday.

"That's not what he meant," Biden continued. "That's not what he has said, since then, for the last year, or thereabouts. And so, I think, that he's fully capable of understanding what's going on."

ABC News' Sunlen Miller and Bret Hovell contributed to this report.