Also, the concern of inviting an error. If the defense has waived the instruction, no fair complaining about it later. So, since Wickersham didn't waive the instruction, the ruling should be reversed.
Someone arrested and sitting in jail, based on probable cause gets top priority (because there has been no review by a legal authority yet; just cops; were they rightfully or wrongfully arrested?).
First question: what does the law provide? This governs what she can say is a crime. Caselaw determines aspects of how the case will be interpreted and handled. Then there's the matter of evaluating the evidence: is it admissable, reliable, does it meet the elements, etc.?
Looking at paper, not interviewing witnesses, going to crime scenes, etc. So, before charging, she needs the get the feeling that a conviction at trial is likely. Actually a lot of police are doing less arresting these days, because they are catching on to this. You shouldn't start a legal action that won't end your way: it's not appropriate for the government, and it's also a waste of resources.
So, is a jury likely to convict, based on what we have (or strongly expect to get)? If not, decline the case.
The end game isn't just conviction/judgment. There's also the question "do I want to get a conviction for this conduct?" and can the criminal justice system do something meaningful to address the conduct? A public safety threat is an obvious case. In big cases, in general, it's easy to make the call. What about conduct that's not so bad, though? For example, the homeless chronic alcoholic who gets unruly and is a menace on the street. So what can we achieve here, via conviction?
She gets descriptions of conduct only, not criminal (sometimes) or medical history. So she doesn't necessarily know all of what's involved. And she needs to make a judgment: should the government devote its resources to this particular social problem? What can we accomplish? There's not always a good answer.
She can't say we're not going to charge drug abusers, because right now that's the only they can get into a treatment bed (once they're on probation). Without this, there's no national health care/mental health system help for them, etc. She knows she is abusing the system when she charges a mentally ill person in order to get them into Mendota. Jails are our new mental health system. But the way things are, the criminal justice system winds up dealing with addicts/mentally ill, and then gets criticized for dealing with those populations. A large number of offenders have problems and treatment needs.
So, anyway. Is there a social good to be had by intervening in the life of this person? For the alcoholic, probably none. It's getting so there's none for drug abusers, also. 85% of the people in the system have substance abuse issues. So these tend to get "county ordinanced," and the person goes back to State St.
Does not like "Truth in Sentencing," because it eliminates the notion of rehabilitation. Judges, by the way, don't have access to a great deal of informaiton. It's routine to do 99 hearings in a day (final conferences). They want a joint recommendation for sentencing-- they're not sentencing, they're rubber-stamping. And both sides have less and less time to devote to each case, so things are getting shoddy.
She doesn't consider matters of degree so much (i.e., plea bargains, defense resources): it's more a decision of should any resources be devoted to the matter. If so, then proceed. It's not her office's job to figure out how jails get paid for, etc.
There have been policy decisions about not prosecuting certain offenses (Operating After Revocation, e.g.), because of lack of prosecutorial resources (except in Operating Under the Influence cases, because there's a public safety concern there). Ironically, revocation because of speeding isn't treated the same way. And anyway, nobody in Dane County will put anyone else in jail for that. Note that there are a lot of unlicensed drivers out there. State Patrol (who pretty much do only traffic law) are pretty sad about this.
She did LAIP, and wanted to be a PD, but decided the charging decision had more impact. You have to be pretty much dirt poor to get a PD these days (the standard has really worsened-- the "cost of living" part has not changed since 1987). Dane County has heroin, but not meth. Other counties, it's the opposite.
Dan asks a good question about race. In her view there are a disproportionate number of minorities in the criminal justice system; they're treated disproportionately in many other areas (education, housing, employment, healthcare, etc.), and this is one result. It's a big social problem, and a symptom of racism in our society. Interesting distinction between rich coke users and crack users: one does not come to the attention of the system. The other doesn't have a house to be private in, or money to pay for the drug; they have to deal with untrustworthy sources, bad deals, etc., and all in public. So you get fights, debts, etc., that you do not with the other population. That is what causes drug prosecution, and that's why you get more minorities prosecuted for it.