Radley Balko argues that judicial elections politicize criminal-justice policy:
How to reverse or ameliorate the damage already done is a debate we'll be having for decades. But there is one change that could at least stop the bleeding: less democracy. As New York Times reporter Adam Liptak pointed out in a 2008 article, America's soaring incarceration rate may be largely due to the fact that we have one of the most politicized criminal justice systems in the developed world. In most states, judges and prosecutors are elected, making them more susceptible to slogan-based crime policy and an electorate driven by often irrational fear. While the crime rate has fallen dramatically since the early 1990s, polls consistently show that the public still thinks crime is getting worse.
In response to these fears, legislators have increasingly eroded the discretion of prosecutors and judges (already subject to political pressures) in charging defendants and imposing sentences. Under the theory that more punishment is always better, lawmakers have imposed mandatory minimum sentences, made parole and probation more difficult, and decreed that mere possession of drugs above a certain quantity is automatically treated as distribution. The democratic demand for such policies may be clearest in California, where it is relatively easy to pass legislation through ballot initiatives. Such initiatives have led to some of the toughest crime policies in the country—and nearly twice as many prisoners as the state's prisons are supposed to hold.
I think part of the reason for this is that crime actually isn't a problem that's on everyone's minds these days, but it's the kind of thing that's likely to take center stage in a judicial election. So while with some exceptions, we don't really see as much tough-on-crime politicking as we used to, a judicial race is the kind of contest in which those issues become more important. Tough-on-crime credentials are probably less important now for an appointed judge than they've ever been.
Thirty-eight states elect their judges, by the way, which honestly makes me a bit uncomfortable, especially since the Citizens United decision makes the idea of an "independent" elected judge even more unlikely. Rick Hasen and Dahlia Lithwick point out today that between 2000 and 2009 more than $200 million has been spent on judicial elections. The potential for impropriety here is arguably worse than with, say, congressional elections, since judges are meant to be a check on legislatures. That becomes less likely when interest groups can buy influence with both branches. It's not like appointed judges are in any sense completely insulated from partisan politics, but the direct financial incentive isn't there.
Incidentally, this is why I dislike both ballot initiatives and judicial elections. We're not a direct democracy for a reason, and a judge worried about re-election is even more likely to tailor his decision to public opinion rather than the law. Judicial elections aren't just bad because they politicize criminal-justice policy; they're bad because they politicize everything that comes across a judge's desk.