"We're going to make sure that we do this in the appropriate way and that appropriate balance is struck," U.S. counterterrorism adviser John Brennan carefully and tellingly put it on Fox News Sunday. Brennan said that Obama tries to "balance our commitment to human rights" as well as "to carry out our relationships with key countries overseas." Less than two months ago, the police chief of Chongqing rushed into an American consulate to confess his boss's most heinous abuses -- including his role in the murder of a British citizen -- and to seek asylum. The U.S. officials turned him away, and the police chief was arrested. This isn't the same situation -- the police chief had committed his share of crimes as well, and Chen Guangcheng is one of China's most successful activists and one of its best known abroad -- but the police chief's case highlights how sensitive the U.S. is about upsetting China's leadership.

If Chen Guangcheng is still locked up in an American diplomatic office, he poses a remarkable challenge to President Obama, one that asks how U.S. foreign policy under his leadership balances American ideals with American interests, whether he is able to achieve both, and, if not, which he will privilege. Obama's foreign policy team, and possibly Obama himself, face a question that is about more than just the fate of this one lawyer, or even about the U.S.-China relationship. It's about the role that America plays in the world, what we do with all the military and economic power at our fingertips.

It's hard not to think of the clichéd action movie climax, when the hero is forced to choose between saving, say, the sidekick or the love interest. He always managed to save both -- it makes for a better ending -- but the scene is compelling because it's an impossible choice, and because in saving one he is condemning the other. Chen's flight to a U.S. diplomatic building forces Obama to choose between ferrying Chen out of China or keeping him there, between human rights or diplomacy, between America's image in the world or its political capital with Beijing, between making China a little bit more democratic or a little bit more cooperative. Obama might be able to have it both ways, like the Hollywood hero, but he will probably have to sacrifice something.

How Obama deals with Chen Guangcheng may say more about his foreign policy and what it values than maybe any other such crisis he has faced during his presidency. That's not because Chen is so important; he is important, but not anywhere near the scale of Iran or North Korea or the Arab Spring. It's because his dilemma forces Obama to choose between two starkly different visions of American foreign policy.

In one sense, freeing this one dissident would risk daunting costs to Obama's agenda abroad; in another, to bring Chen to freedom would seem the very embodiment of American power at its brightest. A blind man of humble origins, Chen got his start fighting for disabled rights in a country that barely recognized them, and ended up taking on some of his government's cruelest abuses and most powerful interests. The U.S. State Department has previously called for his release. And, if he's seeking refugee status, the U.S. is probably obligated under international law to grant it.