Asked about the Vatican’s ability to thwart high-tech eavesdropping, Cardinal Edmund Casimir Szoka, the governor of Vatican City, said, "We have the capability of doing that…. I think our security for the Vatican city-state is pretty good."

Szoka, one of three cardinals in charge of preparing for the conclave, spoke during an interview before the cardinals imposed a gag rule on themselves.

Security measures for the conclave follow directives laid out in 1996 by Pope John Paul ll, who rose to prominence in Poland during the Cold War and forged a modern, media-savvy papacy. He was well aware of the hard-nosed political realities of technology and espionage. He knew that governments, the media or others might be tempted to spy on the conclave.

Nonetheless, the pope designed an election process that offers new comforts and freedom of movement for participants. Rather than being cooped up in monastic quarters next to the Sistine Chapel this time, the cardinals will reside in a new hotel-like building known as the House of St. Martha. They will be shuttled in buses to daily sessions at the Sistine Chapel and will be allowed to stroll on the Vatican grounds.

Security duties at the Vatican are divided between the pope’s Swiss Guard and special details of the Italian national police and paramilitary Carabinieri. By treaty, Italian law enforcement agencies often handle complex policing issues, including the detection of terrorism threats, said a high-ranking Italian police official.

The Vatican has a small team of experts, including former Italian police officers, for sensitive internal security tasks, said the official, who like others interviewed asked not to be identified because of the sensitivity and secrecy of the issue.

"Although we work closely together, Italy is finally a foreign state for the Vatican and they don’t ask us to get involved in such a delicate matter," the police official said.

Over decades of fighting the Mafia and terrorism, Italian law enforcement has developed strong expertise with wiretaps and other forms of surveillance. In recent years, Italian anti-terrorism investigators have impressed European colleagues with a light-footed, slick-fingered capacity for planting minute listening devices in homes, cars and, in the case of Muslim suspects, even in the mosques they frequent.

Asked about strategies for eavesdropping on the conclave, a veteran Italian anti-terrorism investigator said his top concern as a counter-surveillance expert would be tiny bugging devices that are readily available in both the private and public sectors. A traitor on the inside could try to slip a bug or bugs into the target areas, he said.

"That would be ideal," the investigator said. "The question is how many you use and where you put them. It depends on the size of the room and who you want to listen to. You are going to have a lot of people talking in there."

The Vatican has at least two security experts who will conduct intensive electronic sweeps of the chapel, the residence and other areas this weekend before the cardinals sequester themselves, said an Italian journalist who covers the Vatican. The experts will check carpets, light fixtures, furniture, electronic devices and other classic hiding places, according to the journalist and other sources. There will also be daily anti-bugging sweeps during the conclave, the sources said.

The anti-terrorism investigator cited another favored method for snooping: using radio waves to convert a cellphone, unbeknownst to its owner, into a clandestine microphone.

There are no plans, however, to go to the extreme of subjecting cardinals to pat-down searches, said an Italian journalist who covers the Vatican and asked not to be named.

The Vatican has also girded against the use of powerful long-range microphones that can pick up conversations through walls, Cardinal Szoka said.

"They’d have to get very close to do that," Szoka said. "And it’s not very easy to get close to the Sistine Chapel, because first of all they’d have to get inside the Vatican walls and that won’t be easy. And then the area around the chapel will be totally blocked off."

Moreover, the efficacy of long-range microphones is often limited by interference from incidental noises, the veteran anti-terrorism investigator said.

"If there’s too much noise, you really have trouble making out the conversation you want to hear," the investigator said. "That would be a problem."

There is additional speculation about the threat of listening devices that can employ laser technology and are especially hard to combat. Theoretically, the Vatican specialists could create a static "umbrella" as a defense.

Despite talk about powerful surveillance tools, old-fashioned "human intelligence" should not be underestimated, experts said. Church officials have tried to keep to a minimum the number of waiters, bus drivers, cleaners and other personnel at the conclave, choosing longtime Vatican employees whenever possible and screening them thoroughly, sources said.

Of course, the cardinals themselves remain a potential source of leaks.