Meeting nearly daily, U.S. officials had hoped former NSA contractor Edward Snowden would slip up. He didn’t. (Vincent Kessler/Reuters)

While Edward Snowden was trapped in the transit zone of Moscow’s Sheremetyevo Airport last year, U.S. officials were confronting their own dearth of options in the White House Situation Room.

For weeks, senior officials from the FBI, the CIA, the State Department and other agencies assembled nearly every day in a desperate search for a way to apprehend the former intelligence contractor who had exposed the inner workings of American espionage then fled to Hong Kong before ending up in Moscow.

Convened by White House homeland security adviser Lisa Monaco, the meetings kept ending at the same impasse: Have everyone make yet another round of appeals to their Russian counterparts and hope that Snowden makes a misstep.

“The best play for us is him landing in a third country,” Monaco said, according to an official who met with her at the White House. The official, who like other current and former officials interviewed for this article discussed internal deliberations on the condition of anonymity, added, “We were hoping he was going to be stupid enough to get on some kind of airplane, and then have an ally say: ‘You’re in our airspace. Land.’ ”

U.S. officials thought they saw such an opening on July 2 when Bolivian President Evo Morales, who expressed support for Snowden, left Moscow aboard his presidential aircraft. The decision to divert that plane ended in embarrassment when it was searched in Vienna and Snowden was not aboard.

A year later, Snowden appears to have moved further beyond U.S. reach. His expiring asylum status in Russia is expected to be extended this summer. Negotiations between his attorneys and the Justice Department about a possible deal to secure his return have been dormant for months.

U.S. officials offer conflicting accounts of how much they know about Snowden’s situation in Russia.

“It’s an ongoing investigation,” U.S. Attorney General Eric H. Holder Jr. said in an interview. “We have done the appropriate things at this stage of the investigation, and we know exactly where Mr. Snowden is.”

Others said the United States lacks answers to even basic questions about Snowden’s circumstances, including where he lives and — perhaps most important — the role of the Russian security service, the FSB, in his day-to-day life.

Asked whether the United States knows Snowden’s location, a U.S. official regularly briefed on the matter said, “That’s not our understanding.”

The gaps persist despite Snowden’s ability to meet with U.S. journalists in Moscow and make high-profile appearances, including during a call-in show with Russian President Vladi­mir Putin.

Michael McFaul, who served as U.S. ambassador to Russia until February, said he never had detailed information on the American fugitive’s whereabouts. “I do not know where Mr. Snowden is living, what his relationship to the Russian government is or how he makes a living,” said McFaul, who has returned to the faculty at Stanford University.

Several U.S. officials cited a complication to gathering intelligence on Snowden that could be seen as ironic: the fact that there has been no determination that he is an “agent of a foreign power,” a legal distinction required to make an American citizen a target of espionage overseas.

If true, it means that the former CIA employee and National Security Agency contractor, who leaked thousands of classified files to expose what he considered rampant and illegal surveillance of U.S. citizens, is shielded at least to some extent from spying by his former employers.

Snowden is facing espionage-related charges, and the FBI has power to conduct wiretaps and enlist the NSA and CIA in its investigative efforts overseas. But even with such help, officials said, the bureau’s reach in Moscow is limited.

“The FBI doesn’t have any capability to operate in Moscow without the collaboration of the FSB,” said a former senior U.S. intelligence official who served in the Russian capital.

The lack of a warrant deeming Snowden a foreign agent would also cast doubt on the claims of some of his critics. U.S. officials, including Rep. Mike Rogers (R-Mich.), the chairman of the House Intelligence Committee, have speculated that Snowden had Russian help in stealing U.S. secrets and probably works with the FSB now.

Snowden has acknowledged that he was approached by Russian intelligence upon his arrival, but he has said he rejected the pitch and did not bring any classified files with him. He insisted in a recent NBC television interview that he has “no relationship” with the Russian government.

Snowden attorney Ben Wizner, a lawyer with the American Civil Liberties Union who corresponded with his client for this article, said Snowden gets no financial support from the Russian government and does not need it.

Beyond savings from his six-figure NSA jobs, Snowden has received tens of thousands of dollars in cash awards and appearance fees from privacy organizations and other groups over the past year, Wizner said. An organization called the Courage Foundation launched a Web site to raise money for Snowden’s legal defense and listed contributions of $1,356 as of Saturday afternoon.

The apparent stability of Snowden’s situation contrasts with the uncertainty of the eight-week stretch last summer after he had publicly identified himself as the source of a trove of NSA documents but before he secured asylum in Russia — a critical but now closed window in U.S. efforts to catch him.

The burst of activity during that period — including the White House meetings, a broad diplomatic scramble and the decision to force a foreign leader’s plane to land — was far more extensive than U.S. officials acknowledged at the time.

President Obama in particular seemed to strike a dismissive pose, saying on June 27 that he was “not going to be scrambling jets to get a 29-year-old hacker.” Caitlin Hayden, a spokeswoman for the National Security Council, said Obama’s remark referred only to the prospect of using military assets. “The president made clear he wouldn’t,” Hayden said in recent statement the The Washington Post. “Not because we weren’t working hard to get Snowden back to the U.S.,” but because it was a law enforcement matter.

From the outset, the pursuit of Snowden was led by the FBI. Lon Snowden, the fugitive’s father, said FBI agents descended on his house within hours after a video of his son identifying himself as the source of the NSA leaks appeared on the Web site of the British news outlet the Guardian.

“I spoke to them approximately four hours on the 10th of June,” Lon Snowden said. Later, the FBI offered to send the elder Snowden to Moscow as part of an effort to deliver a scripted pitch to his son to turn himself in and return home. A former officer in the Coast Guard, Lon Snowden was initially cooperative with the bureau but became angered as his son was depicted by U.S. officials as a traitor.

“I came to know that they were not functioning in good faith” and turned down the trip, Snowden said.

By then, Monaco was convening meetings nearly every day at the White House. Among the participants were the CIA’s head of counterintelligence, FBI Deputy Director Sean Joyce and McFaul, who often took part by videoconference in sessions that got underway well after midnight in Moscow.

The meetings “were not just about Edward Snowden the fugitive” and covered subjects including assessments of the damage the leaks had caused, Joyce said. But there was a constant search for ideas to recover him. “There were several things that were sort of ongoing,” Joyce said, declining to be more specific. “None of them actually panned out.”

Many of the meetings were followed by a stream of calls from U.S. officials to Moscow. Then-FBI Director Robert S. Mueller III made more than half a dozen direct appeals to his FSB counterpart, Alexander Bortnikov, officials said, all for naught.

U.S. officials said the aim was to convince Putin that turning over Snowden would bolster the U.S.-Russia relationship at a trivial cost to Moscow. But even those making the appeals regarded them as long shots.

“Key players in this were very pessimistic,” said a former U.S. intelligence official involved in the discussions. “The FBI and CIA would have put the chances of cutting some deal with the Russians to send him home at close to zero. This was just too juicy for Putin.”

Against those odds, the Obama administration focused on the prospect that Snowden — who had cited interest in finding asylum in Iceland or Latin America — would abandon his Moscow perch.

State Department and CIA officials pressured countries seen as potential destinations to turn Snowden away, reducing his options to a handful hostile toward the United States. Among them was Bolivia, whose president had signaled publicly that he would consider giving Snowden asylum.

“Why not?” Morales said during a July visit to Moscow. “Bolivia is there to welcome personalities who denounce — I don’t know if it’s espionage or control.”

In interviews, U.S. officials acknowledged that they had no specific intelligence that Snowden would be on Morales’s plane. But the Bolivian leader’s remark was enough to set in motion a plan to enlist France, Spain, Italy and Portugal to block the Bolivian president’s flight home.

“The United States did not request that any country force down President Morales’s plane,” said Hayden, the National Security Council spokeswoman. “What we did do . . . was communicate via diplomatic and law enforcement channels with countries through which Mr. Snowden might transit.”

Another U.S. official described the effort as a “full-court press” involving CIA station chiefs in Europe.

As it crossed Austria, the aircraft made a sudden U-turn and landed in Vienna, where authorities searched the cabin — with Morales’s permission, officials said — but saw no sign of Snowden.

The initial, official explanation that Morales was merely making a refueling stop quickly yielded to recriminations and embarrassment.

Austrian officials said they were skeptical of the plan from the outset and noted that Morales’s plane had taken off from a different airport in Moscow than where Snowden was held. “Unless the Russians had carted him across the city,” one official said, it was unlikely he was on board.

Even if Snowden had been a passenger, officials said, it is unclear how he could have been removed from a Bolivian air force jet whose cabin would ordinarily be regarded as that country’s sovereign domain — especially in Austria, a country that considers itself diplomatically neutral.

“We would have looked foolish if Snowden had been on that plane sitting there grinning,” said a senior Austrian official. “There would have been nothing we could have done.”

Diverting Morales’s plane was more than a diplomatic setback. It also probably caused Snowden to abandon any idea of leaving Russia, squandering what Monaco had described as “the best play” for the United States.

A year after his arrival in Moscow, Snowden is seeking ways to find normalcy. Wizner, his attorney, said Snowden is considering taking a position with a South African foundation that would support work on security and privacy issues.

Snowden has also fielded inquiries about book and movie projects.

“Any moment that he decides that he wants to be a wealthy person, that route is available to him,” Wizner said, although the U.S. government could also attempt to seize such proceeds.

Wizner declined to discuss where Snowden lives, or how he secured an apartment in a city where such transactions require government involvement — except to indicate that Snowden’s Russian attorney, Anatoly Kucherena, has helped with such arrangements.

Snowden’s relationship with Kucherena, who has close ties to Putin and serves on an FSB advisory board, has fueled speculation that he is working with the Russian government.

McFaul, the former ambassador, raised other questions, including how Snowden has managed to arrange interviews with prominent U.S. journalists — all requiring Russian visas that could not be obtained without FSB approval — but has yet to grant such access any Russian reporters.

“Many Russian journalists are eager to interview him and ask these questions, but so far he has refused,” McFaul said.

Snowden’s critics and supporters do occupy a thin strand of common ground. They agree that Snowden is probably under nearly constant scrutiny by the FSB and lives a life that is constrained by his dependence on the government that granted him asylum.

“When Snowden says that he has ‘no relationship’ with the Russian government, he means that he hasn’t cooperated with their intelligence services in any way and that his asylum isn’t conditioned on cooperation,” Wizner said. “Of course, the Russian government could choose to expel him at any time.”

Sari Horwitz, Ellen Nakashima and Julie Tate contributed to this article.