Former NSA contractor and leaker Edward Snowden. (GUARDIAN/GLENN GREENWALD/LAURA POITRAS)

They say that idealists make for the best activists, but they do not always make for the sagest navigators of international politics. Edward Snowden's ideals, which he said led him to reveal the U.S.'s secret surveillance programs, have landed him in the middle of some of the world's most powerful actors. The 30-year-old and his mission appear to have been subsumed by forces much larger than himself, a world that turned out to be driven less by forces of good or evil than by the hard-nosed politics of international affairs.

Snowden seems to have assumed that good people would share both the logic and single-mindedness of his idealism. What he did not appear to anticipate were the risks that foreign governments would see in sheltering him and the degree to which they would consider their own interests over those of a 30-year-old American exile. For all his understanding of computer systems and his conviction in Internet freedom, his grasp of the international system to which he has since surrendered his future appears to have been somewhat weaker. And that, rightly or wrongly, has left him stranded in Moscow's airport, his fate in the hands of a Russian leader who would seem to embody the opposite of Snowden's ideals.

The trouble started for Snowden not long after he revealed that he was hiding in Hong Kong. He said he would trust in the people of Hong Kong to decide his fate, apparently believing that its democratic institutions and its outrage at U.S. hacking would lead the Chinese special administrative region to shelter him. While many in Hong Kong and mainland China professed moral support for Snowden, that did not translate into the necessary political support. Both Hong Kong and mainland China deal frequently with the United States, after all, and would be naturally cautious about unnecessarily angering Washington. When Snowden began releasing information about U.S. cyber espionage efforts in China – programs in the vein of traditional inter-state spying, practiced by China against the United States as well – he seems only to have heightened China's apparent view that he was not worth the risk. Snowden was sent packing, told that he could not count on the life of a sheltered dissident in Hong Kong.

Initially, Snowden expressed a desire to find shelter in Iceland, which has strong whistleblower protections and a libertarian penchant that would seem to align neatly with his own professed views. But Iceland also is an actor in the international arena, where it has to coexist with the United States. It's governed by people who have lots of responsibilities beyond taking symbolic stands for Internet freedom, including managing the economy and foreign relations. Icelandic voters, after all, recently elected a more right-leaning government that ran on promises of economic revival, has sought closer ties to the United States and is downplaying the possibility of sheltering Snowden.

Other countries that might have taken in Snowden appear to have since backed away as well. Ecuador, which is sheltering WikiLeaks chief Julian Assange in its London embassy, initially hinted it would grant Snowden asylum, but has since softened that support considerably. Assange's own activism within the Ecuadorian government appeared to make things worse: for all Ecuador's interest in tweaking the United States, it did not seem to enjoy the appearance that Assange was "running the show," as one diplomat put it. Ecuadoran President Rafael Correa was happy to help activists like Assange and Snowden when it served his interests as a national head of state, but not to subsume those interests to these two non-national Westerners. That distinction might have been clear to close observers of Ecuador and Correa, whose policies at home suggest he is far from a libertarian fellow-traveler. But to activists prone to dividing the world into good guys and bad, it might come as a surprise that a once-staunch ally like Correa might retreat once the situation no longer favors his interests.

And that brings Snowden to the transit area of a Moscow airport, where's he's been marooned since arriving several days ago from Hong Kong. A few short weeks after declaring he could trust in the people and institutions of Hong Kong, he appears to have come under the control of the Russian government, which now has the ability to restrict his travel not just internationally but even within the airport itself.

Snowden's new boss is Russian President Vladimir Putin, who has taken to speaking openly about how the American asylum-seeker should behave. "Russia never hands over anybody anywhere and has no intention to do so," Putin told a news conference on Monday. "If he wants to remain here there is one condition – he should stop his work aimed at inflicting damage on our American partners, no matter how strange this may sound coming from me."

Yes, even Moscow, which has been happy to shelter everyone from British spies to deposed dictators, and has punished what it sees as American misbehavior, for example, by banning American adoptions of Russian orphans, can see limits to angering the United States.

Heads of state tend to get and stay that way by careful pragmatism, by carefully balancing their nation's interests and by caution in the international arena. That holds true for the governments of Hong Kong and Iceland as well as leaders like Putin and Correa. Knowing how to navigate those webs of interest can be notoriously complicated for even the most seasoned veteran. For an activist like Snowden, enough of an idealist to flee his country and reveal secret programs he believes to be wrong, diplomatic maneuvering does not always come naturally.