Public Policy Is Not Science Even Though I Agree It Should Be More Like It
It's like business decisions. You weigh the risks and balances and sometimes you have to make a decision to act without being certain about your data because the risk of inaction is too high. Clinton underestimated Al-Queda and we got 911. Bush may have overestimated Saddam and the Iraqi's got freedom from a bloody tyrant. Not hard to see which made the better risk reward judgements on the use of force.
On the other hand, we should learn from the history of the 80's and 90's when it comes to tax policies.
Regards,
Mark