That's the central question of Steven Spielberg's new Cold War drama Bridge of Spies, which just released its first trailer, and it was a question hurled at real-life attorney James B. Donovan (played by Tom Hanks) when he represented the captured Soviet spy Rudolf Abel in 1957.

Donovan lost that case, which threatened to destroy his reputation with the public, but what Donovan was defending was the ideal that everyone deserves a legal defense – an argument about how we detain and prosecute attacks on our country that endures from the Cold War to today's War on Terror.

Later, Donovan would be involved in another effort to release Abel from captivity, but again, what may sound like aid to a enemy was actually a mission on behalf of the American government. Donovan was enlisted to use Abel as a bargaining chip to reclaim one of our own: Francis Gary Powers, a U.S. pilot shot down over Soviet airspace in 1960 while flying a U-2 spy plane.