Leandro Aragoncillo, the former vice-presidential aide accused of passing U.S. intelligence to opposition Philippine politicians, may be the most recent case of an alleged spy in the White House, but he's not the first.
"You've had other instances where other individuals have leaked … from the White House, as well as other agencies," said Peter Earnest, a 36-year veteran of the CIA and the founding executive director of the International Spy Museum in Washington.
The history of spying for and against the United States dates back to before the nation's founding. And that history can be murky: To this day, all that's known of some spies are their code names. Some doubt the guilt of convicted spies. And some historical figures who never faced espionage charges now are widely thought to have been moles.
Some of those supposed spies include former officials with White House access.
For example, Earnest said, newly-declassified U.S. and Soviet intelligence backs longtime allegations that Alger Hiss, part of the presidential delegation to the Yalta conference that divided Europe after World War II, and Lauchlin Currie, a longtime U.S. government official and aide to President Franklin D. Roosevelt, were Soviet spies in the 1930s and 1940s.
More recently, in 1997, the FBI was said to be looking for an Israeli agent identified only by the code name "Mega" in decrypted communications that suggested he had penetrated the Clinton White House.
Neither Hiss nor Currie was convicted of espionage. Both maintained their innocence, and continue to have defenders even after their deaths in the 1990s.
Hiss, though accused of spying during highly-publicized trials in the late 1940s, ultimately was convicted of perjury. Much of the evidence against Currie remained classified during his lifetime, perhaps the reason he never was tried. But the native Canadian, a naturalized U.S. citizen, was blocked from re-entering the United States in the 1950s. He moved to Colombia, ultimately gaining citizenship there and becoming a celebrated government economic advisor.
'Money, Ideology, Revenge and Ego'
Frederick Wettering, a 35-year CIA veteran, now retired and teaching a course on the history of espionage at Lake-Sumter Community College in Florida, said turncoats historically tend to volunteer as spies, rather than get recruited -- and they have displayed a variety of motives.
"The acronym I use is MIRE," Wettering said. "Money, ideology, revenge and ego are the main reasons they do that."
The Revolutionary War turncoat Benedict Arnold -- a recruit of the British, not a volunteer -- may have changed sides as revenge for professional slights or for relief from financial problems. Several spies in the 1930s and 1940s volunteered to spy for the Soviet Union because of ideology.
More-recent spies seem to have been in it for the money: John A. Walker and Aldrich Ames, spies for the Soviets who pleaded guilty in 1985 and 1994, respectively, "did it strictly for the money," Wettering said. Robert Hanssen, an FBI agent sentenced in 2002, was for decades a highly-paid spy for the Soviets and then the Russians.
Officials told ABC News that former Philippine President Joseph Estrada and his aides used small amounts of money and appeals to ethnic loyalties to recruit Aragoncillo, 46, a naturalized Filipino-American FBI analyst and former White House aide to vice presidents Al Gore and Dick Cheney. Aragoncillo is said to have been a half-million dollars in debt.
Aragoncillo allegedly stole sensitive U.S. intelligence on politicians from the Philippines -- including current President Gloria Macapagal Arroyo. He may have e-mailed purloined information to an alleged Filipino handler, who has pleaded not guilty after being indicted on charges of conspiracy and acting as an unregistered foreign agent. Some of the material in question seems to have wound up in the hands of opposition politicians in the Philippines, including Estrada.
Incidentally, Aragoncillo is not the first American accused of spying for Filipinos. Michael Allen, a Navy radio operator, was convicted of leaking intelligence to the Philippine government in 1987. In the early 1990s, Joseph Garfield Brown, a martial-arts instructor, and Virginia Jean Baynes, a CIA secretary, pleaded guilty to leaking.
George Washington, Spymaster
America's spy history goes back at least as far as George Washington, regarded by many as America's first modern spymaster.
"Washington loved intelligence operations and ran one of the most successful spy rings in American history called the Culper Ring," Wettering said.
The Culper Ring operated mainly in British-occupied New York City and the surrounding areas, and used modern spy techniques such as dead drops, codes, aliases, paid agents and signals. One agent is said to have hung color-coded laundry on New York's Long Island that could be viewed and interpreted by telescope from across Long Island Sound in Connecticut.
At one point, the Culper Ring tipped Washington to a planned British attack from New York on French ships off Rhode Island. The tip led Washington to bluff his own invasion of New York from the south as a diversion, and the British called back their attack.
Many consider the Culper Ring more important to the history of Revolutionary War spying than more well-known spy figures such as Arnold and Nathan Hale.
"In 1984, I went to work for [then-CIA director] Bill Casey as the national intelligence officer in Africa," Wettering said. "Right in front of CIA headquarters, there's a statue for Nathan Hale, and Casey wanted to replace it with a statue of Robert Townsend. Robert Townsend was one of Washington's most successful spies in New York City. … His name didn't come out for 200 years, and he didn't get caught. Hale got caught."
Spies peppered American history after the Revolutionary War, particularly during the Civil War, another period of divided American loyalties. But spy experts look back on the methods of those eras as less modern and effective than those of Washington.
The Cold War sparked a revival for American intelligence, but not before foreigners penetrated the U.S. government.
Though the Soviet Union was a U.S. ally in World War II, records suggest they had infiltrated American government and industry with secret agents much earlier.
The evidence includes records from a code-breaking project known as Venona, in which the United States secretly intercepted and decrypted Soviet communications in the 1940s. When those records were declassified and studied by historians starting in 1995, they seemed to add to the evidence against Hiss, Currie, Julius Rosenberg and dozens of other American officials and scientists.
"The Soviets had pretty thoroughly penetrated the U.S. government in the period of the forties," said Earnest, the spy museum founder who also spent 36 years in the CIA, much of it in covert operations.
"When [Treasury] Secretary Morganthau would come in in the morning, usually two or three people in his office were Soviet agents," Earnest added. "The number of spies we had in the Soviet Union was a big, fat zero."
After World War II and Venona, the United States became more aggressive about placing and ferreting out spies. There had been code-breaking efforts in World War I, and the FBI was formed early in the century, but World War II saw the establishment of the Office of Strategic Services, or OSS -- precursor to the CIA, established in 1947.
The fall of the Soviet Union did not put an end to the spy battles. Because of America's preeminence, though America's friends may deny it, even non-hostile countries and entities -- perhaps including Philippines officials alleged to have gotten information from Aragoncillo -- want to know what America knows.
For example, at the time of the 1997 "Mega" investigation, an Israeli diplomat told the Sunday Times of London that the story was "baseless" because, "Israel is not involved in any kind of espionage or trying to obtain intelligence or trying to obtain intelligence from the United States."
However, the facts suggest they have spied on us. Larry Franklin, a former Pentagon analyst, pleaded guilty this year of passing classified information to Israel via a third party. And in 1986, Jonathan Pollard, a civilian naval intelligence analyst, had pleaded guilty to spying for Israel.
"It's like playing poker," Earnest said. "Every other state in the world wants to know what you've got in your hand."
In addition to fending off threats from friendly nations, the United States now must deploy intelligence agents in a new ideological war. But it's different than the Cold War.
"We clearly are dealing with the spread of elements that are somehow associated with Islamic fundamentalist ideas and are loosely associated with Osama bin Laden," Earnest said. "You're dealing with a non-state entity. When looking at the Soviet Union, it was much easier to grasp the Soviet Union. You had targets."
So what to do now in a more ambiguous struggle?
"That's a very good question," Earnest said. "Where do you deploy your [intelligence] forces?"