A veteran lawyer who could hold the key to Edward Snowden's eventual return to the United States has spoken of his fivedecade career cutting deals for some of America's most notorious spies. Washington-based legal heavyweight Plato Cacheris has been retained by the whistle-blower, who was granted temporary asylum in Russia. And he spoke to the Sunday Morning Post as the first anniversary approaches of former National Security Agency contractor going public in Hong Kong with revelations that mass digital surveillance by the US extended to targets in China. Cacheris, 84, has defended many clients charged under the US Espionage Act, including saving an FBI agent who spied for the Russians from the death penalty and others from long jail sentences. He stressed he could not talk about the Snowden brief, but said he believed his vast experience of defending people charged under the Espionage Act put him in a good position with US government prosecutors. "All cases are unique, but the fact that I have dealt in these types of cases is known by the prosecutors, so they know that we can talk on a level that's a little bit higher than with most lawyers," Cacheris said. "They are far different from routine cases. They are very complex, they are very interesting and yes, they are the cases I enjoy the most. We know what we want to do, how we want to do it and we do not talk to the press until the case is over," Cacheris said. Snowden, 30, left Hong Kong last June when the US charged him under the Espionage Act for leaking classified documents. In January, he said he wanted to return to the US, but only if the whistle-blower protections laws were amended to cover national security contractors. "Returning to the US, I think, is the best resolution for the government, the public, and myself, but it's unfortunately not possible in the face of current whistle-blower-protection laws, which through a failure in law did not cover national security contractors like myself," Snowden told the "Free Snowden" website. He said the current law "was never intended to be used against people working in the public interest, and forbids a public interest defence". Snowden added: "This is especially frustrating, because it means there is no chance to have a fair trial and no way I can come home and make my case to a jury." Snowden hired Cacheris last summer, according to a New York Times article earlier this month. Over the past 20 years, he has been working closely with John Hundley, a partner at his law firm Trout Cacheris, when dealing with espionage cases. "It's very collaborative but as I have grown older, he has done more and more of the work. For example in the Tai Shen Kuo case, he did most of it," Cacheris said, referring to the 2008 case of a Taiwanese-born US citizen who was caught spying for the Chinese government. Other high-profile cases that Cacheris has worked on include defending former US attorney general John Mitchell, who was implicated in the Watergate scandal, former CIA officer Aldrich Ames, who spied for the Soviet Union and Russia, and former FBI agent Robert Hanssen, who sold state secrets to Russia. "[The prosecutors] were threatening the death penalty, but we bargained them down to a life sentence," Cacheris said of the 2001 Hanssen case. Cacheris, explaining his approach as a defence attorney, said: "I find out what a case is about by an extensive interview with the client ... getting from him all the information he has, because in any case - and in espionage cases in particular - the government does not know everything." He added: "They want to know what was given away - that was of importance to this government - to a foreign government." "I try to see that their rights are protected" With such an eye-catching first name, Washington-based defence lawyer Plato Cacheris was never going to struggle for an audience. But don't ask this first son of Greek-American immigrants to be philosophical about his clients' crimes, regardless of their severity. "As a defence lawyer, in the cases that I accept, I try to do the best for them, no matter what they've done. I'm not bothered by the fact they've committed these terrible crimes. I try to see that their rights are protected and they get the best disposition that they can possibly get. I don't lecture them on what they've done; I don't believe in that. What's done is done; now the question is 'how can we come out of it the best way possible way?'" he said. Cacheris, 84, includes on his client list the men at the centre of the two biggest spy scandals in modern US history: former FBI agent Robert Hanssen and ex-CIA agent Aldrich Ames who spilled state secrets for cash and valuables to Moscow. Along the way he has built up the reputation, contacts and considerable clout that only 49 years defending spies could bring and even former NSA contractor Edward Snowden has retained his services. "I've dealt with the prosecutors for so long that they know me and we have a good relationship. It's my practice not to be antagonistic to the prosecutors even though they want to do one thing and I want to do another. We work it out. They have, I think, trust in me and I have trust in them." His work with Snowden is off-limits but Cacheris did say he enjoyed the challenge of defending defendants on espionage charges. "These cases are significant and the consequences to the defending clients are severe," he said. Born to Greek immigrants in Pittsburgh, Pennsylvania, in 1929, Cacheris went to high school in Washington. His father, Christos, ran restaurants where the young Plato often worked. His career in law sprung out of an early interest in joining the Foreign Service, part of the US State Department. "As I got older, I was more interested in becoming a diplomat," recalled the father of two adult children who lives in Virginia. He enrolled in the School of Foreign Service in Georgetown and it was a course in law there which piqued his interest. He told the Sunday Morning Post: "Just the fact that you could help people by being an effective attorney, I thought that was worthy. Then the Korean war came along and I was required to serve in the Marine Corps, which I did. As a result of that service, I could get a free law school education." His first case as a defence lawyer was that of Herbert Boeckenhaupt, a US Air Force sergeant on spy charges, in 1967. From there a reputation as a gentleman outside and a vicious combatant inside the courtroom was built. Does he relish the heat of a verbal joust? "I do when I have to", he said. By definition, espionage is intensely political and Cacheris is keenly aware that the climate in which a legal battle on spying takes place can have a huge impact on the outcome, with Hanssen being a case in point, he said. Hanssen, who sold US secrets to Moscow for millions of dollars, faced the death penalty but Cacheris negotiated prosecutors down to a life sentence in 2001 - just months before the politically seismic events of September 11. "It's my belief that if we had still continued to negotiate, and 9/11 happened, they would not have given him the disposition we got. That's my opinion. Nobody said that to me but that's my belief because after 9/11, the whole atmosphere had changed." That change heralded a new era of government-sanctioned surveillance and goes to the heart of the debate sparked by Snowden's leaks. No less controversial was Cacheris' role in Monica Lewinsky's legal team. The former White House intern whose dangerous liaison with former US president Bill Clinton lead to his impeachment was back in the news last week after breaking her silence on the scandal in Vanity Fair. In 1998, Cacheris represented Lewinsky, along with co-counsel Jake Stein, and gained her immunity from prosecution. He ranks as his best outcome the case of Michael Soussoudis from Ghana, who was granted freedom from spying charges in return for a guilty plea and lifetime ban from entering the US in 1985. Soussoudis received US secrets from his girlfriend and CIA agent Sharon Scranage during her time in Ghana.