A intelligence analyst interviewed on NPR a few weeks ago reported that the aluminum tubes in question had been purchased by Iraq in the past and used for conventional weapons more than once. While it's possible that they could be using them for something else now, the pattern of behavior doesn't fit.

The evidence being presented is so flimsy and circumstantial it would never stand up in a court of law in the US for any crime, let alone one where the death penalty is being considered. Why are some members of the US administration considering this enough evidence to exact the death penalty on Iraqi civilians?