On No Reasons and Mixed Reasons

Per Doug's query below, I think that "no reason" really means "any reason", but can include reasons like: I was forced to choose and so I chose X, not because I really prefer X, but because I preferred some choice to no choice (think Sophie’s Choice). Of course, the “for any reason or no reason” formula was most famously deployed to describe the traditional understanding of peremptory strikes in jury selection. Since the formula permitted prosecutors to strike potential jurors on the basis of illegitimate criteria, the Batson doctrine was developed to place some safeguards on what previously had been unconstrained discretion, essentially modifying the phrase to “for any reason, except an impermissible reason.” Ungainly, but perhaps not unworkable. In the Batson context, an interesting problem (about which I’ve written) has arisen in which the proponent of a strike will state both a neutral reason and an impermissible reason in the attempt to defend the strike. Courts have tended to treat this instance as a causation problem, evaluating the permissibility of the strike based on an analysis of whether the impermissible reason was the “but-for” cause of the strike.  Since we are talking about trying to get into the head of the proponent to sort out the “true” mixture of motivations, this whole line of inquiry is pretty dubious, to say the least.  In the context in which Doug’s question arises -- prosecutorial discretion -- there is no comparable limiting procedure to ensure that prosecutorial declinations are not the product of race discrimination or some other illegitimate consideration. Maybe there should be. Maybe victims of alleged crimes, or others, should be entitled to a reason for a declination, at least in cases in which the victim could make out a prima facie case of racial discrimination in the declination. (Might be tough.) Pretend we had such a mechanism. What do you do with the case in which the prosecutor then admits that he declined to prosecute X because he was a) white, and b) a first-time offender, and he always gives first-time offenders a break? Should we demand some showing that racial bias actually "caused" the declination? Doesn't that really seem beyond silly, given the evidence of racial bias already adduced?