Douglas Berman, of the Sentencing Law and Policy Blog, explains why he thinks that courts, and particularly the U.S. Supreme Court, devote to much attention to death penalty cases. The main points:
1. The death penalty is a regional issue with little or no impact in most of the country.
2. Death is so different that it often can skew the development of the law.
3. Innocence issues aside, the very worst defendants get (very limited) benefits from all the time and attention give to capital cases.
4. Our massive criminal justice systems implicate many issues that get little attention.
The strongest counterpoint is not the one he is responding to in that post. Instead, the best reason to focus on capital punishment is a canary in the mine theory. High capital punishment rates in places like Texas are a symptom of particularly sick criminal justice systems. It is a regional issue because the South it far behind the rest of the county in the fairness of their criminal justice systems, particularly at the state level. After the South, the federal system's draconian sentencing is ailing most seriously.
This isn't to say that other states are paragons of virtue. California's three strikes law, for example, is a nightmare, and the grittier day to day operations of California's system are nothing to write home about. But, most state court criminal justice systems outside the South are far less out of whack.