"An Insane Proposal on Mental Evidence"

Kent Scheidegger has this post at Crime & Consequences, suggesting that limiting the ability of the government to respond to defense evidence on mental state could have untoward consequences for crimnal defendants:

Once upon a time, the offense of driving while intoxicated meant driving while actually intoxicated.  Blood alcohol level raised a presumption, but the defendant could rebut it.  (Contrary to myth, impairment is not a simple function of blood alcohol level.)  Sandstrom v. Montana said no more presumptions.  Per se alcohol laws said no more rebuttal.  DUI defendants were much better off with the now-forbidden presumption.