The issue is not that judges have the discretion to impose lower penalties in cases that warrant it, the issue is that their need to do so has become the rule rather than the exception. There are supposed to be checks and balances: Congress should enact a sensible maximum penalty so that it limits the scope of the damage when the judiciary makes a mistake, and judges have discretion to impose lower than the maximum penalties in specific cases to limit the scope of the damage when Congress makes a mistake.
But Congress has abdicated their role. They've taken the judicial discretion that ought to have been a rarely needed relief valve and built the entire criminal justice system on top of it by imposing ludicrous maximum penalties and leaving it to the courts to sort it out. In consequence the check that Congress is supposed to be imposing on the courts effectively no longer exists, and if the courts get it wrong then there is nothing to stop it.
Throw in that the plea bargaining system bypasses even the courts in the overwhelming majority of cases and you have the recipe for prosecutorial discretion becoming outcome determinative.
The maximum sentence is not the target sentence. The target sentences are given by the federal sentencing guidelines. Judges have the discretion to give lower sentences in situations that warrant them, and have the discretion to go up to the maximums in situations that warrant them. But by and large they hew pretty closely to the sentencing guidelines.
I'm not sure how that addresses the issue of too much judicial latitude on the top end. Giving judges discretion to reduce a sentence makes good sense. Giving them discretion to go up (or equivalently to go anywhere which is "down" from the stars) is abdicating the duty of Congress and inviting injustice, and the uncertainty provides undue leverage to prosecutors in plea negotiations, especially for an accused with little experience with the justice system. And the uncertainty isn't just in the judge's adherence to the guidelines, it's in what goes into the calculation. The guidelines are obviously very complicated ("43 offense levels" etc.) and you don't get to present your case to a jury and learn their findings of fact before deciding to take a plea, so whenever there is a fact in dispute that causes an order of magnitude difference in the guideline sentence, the guidelines force the accused to take an unduly large risk in going to trial.
Moreover, the sentencing guidelines are still full of harsh penalties. When Congress presents the authors of the guidelines with a maximum penalty of 25 years, it makes a five year prison term seem generous to the accused, notwithstanding that it is in actual fact an extremely harsh prison sentence in absolute terms.
And, correct me if I'm wrong, whether something is a felony is based on the maximum penalty rather than the imposed penalty. So even if your actual sentence is "only" a number of months under the sentencing guidelines and in practice, you're still a felon for the rest of your life with all of the disqualifications that come with it if the maximum penalty exceeded a year.
I don't think it's too much to ask for Congress to better differentiate between more and less serious crimes and to set appropriate maximum penalties for each.
So basically you want Congress and the Judiciary to only ever make sentences shorter, yes? Now, I do think Us sentences are too long and serve little social purpose, but I'm a rehabilitationist (probably because I'm a Euro utilitarian type), whereas a majority of Americans seem to be retributionist, and deontological ones at that. In general, Americans like throwing the book at criminals, or people they perceive to be criminals.
>So basically you want Congress and the Judiciary to only ever make sentences shorter, yes?
I didn't say "ever" -- if sentences were too low then the maximums should go up, but we are clearly in no danger of that happening because as you point out, "Americans like throwing the book at criminals, or people they perceive to be criminals." There is a reason that we don't elect Supreme Court justices.
But Congress has abdicated their role. They've taken the judicial discretion that ought to have been a rarely needed relief valve and built the entire criminal justice system on top of it by imposing ludicrous maximum penalties and leaving it to the courts to sort it out. In consequence the check that Congress is supposed to be imposing on the courts effectively no longer exists, and if the courts get it wrong then there is nothing to stop it.
Throw in that the plea bargaining system bypasses even the courts in the overwhelming majority of cases and you have the recipe for prosecutorial discretion becoming outcome determinative.