A demonstrator holds a sign with a photograph of former U.S. National Security Agency contractor Edward Snowden and the word "HERO" during Fourth of July celebrations last year in Boston. Investigators say they may never know exactly what Snowden leaked from government computers. Reuters

When he became a National Security Agency whistle-blower, Edward Snowden had nowhere to go. The U.S. revoked his passport and issued an international arrest order; Russia, where he was holed up in Moscow airport's international transit area for months, wouldn't give him a visa; and none of the other countries he petitioned for asylum -- Ecuador, Brazil, France and Germany, among others -- would grant him refugee status.

Finally, Russia, where he now resides, granted him temporary asylum. His permit will run out in mid-2014.

After Snowden's revelations earlier this year, more instances of espionage on foreign countries and U.S. citizens by the NSA have become known. Political leaders, including German Chancellor Angela Merkel and Mexican President Enrique Peña Nieto, learned that their personal phones and email accounts were being monitored.

But nobody took it as personally as Brazil’s President Dilma Rousseff, who called U.S. President Barack Obama to ask for an explanation. Whatever the American president told her wasn't deemed sufficient, and Rousseff canceled her scheduled September visit to the White House. Brazil also put commercial deals and political relationships on hold.

Snowden, as it turns out, hasn't given up on Brazil as a potential long-term asylum destination: he has penned a letter to the country, calling on mutual feelings of personal violation by U.S. authorities, and promising to assist in the fight against political espionage (Brazil led that fight at the United Nation's Human Rights Committee in November). Yet, he doesn't directly ask in the letter to be granted asylum, even though he does write that he needs "permanent political asylum" to continue his struggle for privacy rights.

Here's the letter, as reproduced by Brazilian newspaper Folha de São Paulo:

"Six months ago, I stepped out from the shadows of the United States Government's National Security Agency to stand in front of a journalist's camera.

I shared with the world evidence proving some governments are building a world-wide surveillance system to secretly track how we live, who we talk to, and what we say.

I went in front of that camera with open eyes, knowing that the decision would cost me family and my home, and would risk my life. I was motivated by a belief that the citizens of the world deserve to understand the system in which they live.

My greatest fear was that no one would listen to my warning. Never have I been so glad to have been so wrong. The reaction in certain countries has been particularly inspiring to me, and Brazil is certainly one of those.

At the NSA, I witnessed with growing alarm the surveillance of whole populations without any suspicion of wrongdoing, and it threatens to become the greatest human rights challenge of our time.

The NSA and other spying agencies tell us that for our own "safety"-for Dilma's "safety," for Petrobras' "safety"-they have revoked our right to privacy and broken into our lives. And they did it without asking the public in any country, even their own.

Today, if you carry a cell phone in Sao Paolo, the NSA can and does keep track of your location: they do this 5 billion times a day to people around the world.

When someone in Florianopolis visits a website, the NSA keeps a record of when it happened and what you did there. If a mother in Porto Alegre calls her son to wish him luck on his university exam, NSA can keep that call log for five years or more.

They even keep track of who is having an affair or looking at pornography, in case they need to damage their target's reputation.

American Senators tell us that Brazil should not worry, because this is not "surveillance," it's "data collection." They say it is done to keep you safe. They're wrong.

There is a huge difference between legal programs, legitimate spying, legitimate law enforcement - where individuals are targeted based on a reasonable, individualized suspicion - and these programs of dragnet mass surveillance that put entire populations under an all-seeing eye and save copies forever.

These programs were never about terrorism: they're about economic spying, social control, and diplomatic manipulation. They're about power.

Many Brazilian senators agree, and have asked for my assistance with their investigations of suspected crimes against Brazilian citizens.

I have expressed my willingness to assist wherever appropriate and lawful, but unfortunately the United States government has worked very hard to limit my ability to do so -- going so far as to force down the Presidential Plane of Evo Morales to prevent me from traveling to Latin America!

Until a country grants permanent political asylum, the US government will continue to interfere with my ability to speak.

Six months ago, I revealed that the NSA wanted to listen to the whole world. Now, the whole world is listening back, and speaking out, too. And the NSA doesn't like what it's hearing.

The culture of indiscriminate worldwide surveillance, exposed to public debates and real investigations on every continent, is collapsing.

Only three weeks ago, Brazil led the United Nations Human Rights Committee to recognize for the first time in history that privacy does not stop where the digital network starts, and that the mass surveillance of innocents is a violation of human rights.

The tide has turned, and we can finally see a future where we can enjoy security without sacrificing our privacy. Our rights cannot be limited by a secret organization, and American officials should never decide the freedoms of Brazilian citizens.

Even the defenders of mass surveillance, those who may not be persuaded that our surveillance technologies have dangerously outpaced democratic controls, now agree that in democracies, surveillance of the public must be debated by the public.

My act of conscience began with a statement: "I don't want to live in a world where everything that I say, everything I do, everyone I talk to, every expression of creativity or love or friendship is recorded.

That's not something I'm willing to support, it's not something I'm willing to build, and it's not something I'm willing to live under."

Days later, I was told my government had made me stateless and wanted to imprison me. The price for my speech was my passport, but I would pay it again: I will not be the one to ignore criminality for the sake of political comfort. I would rather be without a state than without a voice.

If Brazil hears only one thing from me, let it be this: when all of us band together against injustices and in defense of privacy and basic human rights, we can defend ourselves from even the most powerful systems."