Unknown and Unknowable

News about a "diplomatic" exchange between the US and Russia over an anti-missile system in Europe and Iran's pursuit of WMDs underscores how little we really know about the threat of nuclear war.

The "we" includes not only those who have watched a half century of posturing on the subject from the outside but, in large measure, the generations of leaders who have been acting as if they knew what they were doing.

From today's leak, we learn that President Obama sent a "hand-delivered" letter to Russian President Dmitri Medvedev three weeks ago saying "the United States would not need to proceed with the interceptor system, which has been vehemently opposed by Russia since it was proposed by the Bush administration, if Iran halted any efforts to build nuclear warheads and ballistic missiles."

This was quickly followed by a Drudge Report banner, "Russia Brushes Off Obama: No "Haggling,'" over a picture of Vladimir Putin with a macho wink.

Under all that non-news seems to be the simple fact that Obama has indicated he is willing to talk about trading off the deployment of a missile system of unknown reliability for a Russian effort of uncertain effectiveness to slow down an Iranian pursuit of weapons, the status of which is not at all clear.

At the height of the Cold War, when JFK was pursuing a nuclear test ban treaty with the Soviet Union, he urged Americans not to leave the debate to "experts," since the survival of the human race was at stake.

Since then, there has been an Anti-Ballistic Missile Treaty (which George W. Bush scrapped), Ronald Reagan's fervent pursuit of a Star Wars system to shoot down nuclear weapons, which was then and still is mostly a pipe dream, and now, as far as we know, in the best-case scenario possibly capable of intercepting a missile launched by "a rogue state."

What we do know is that billions have been spent and we (including our political leaders, unless hundreds of Washington insiders have honored a pledge of secrecy) are not sure about any technology that would protect Americans from nuclear attack.

If Obama is going to change any of this, while he is talking to the Russians, it would help if he could give us all some idea of what is known, unknown and unknowable about the odds of human survival in a nuclear age.