A poster child for the (federal) death penalty?

This AP story discusses the life and crimes of Joseph Edward Duncan III, who would seem to be exhibit A for anyone trying to make a case for the death penalty.  Here are some details on this bad man:

A man accused of kidnapping two Idaho children, killing one of them, after slaughtering their family has confessed to the killings of three other children a decade ago in Washington state and California, federal prosecutors said Tuesday. 

The prosecutors cited the confessions to the old killings in court papers saying they intended to seek the death penalty against Joseph Edward Duncan III, who was indicted last week on charges involving the two northern Idaho children. “The defendant has engaged in a continuing pattern of violence, attempted violence, and threatened violence,” prosecutors said. Duncan “is likely to commit criminal acts of violence in the future that would constitute a continuing and serious threat to the lives and safety of others.”…

The U.S. attorney’s office said Duncan confessed that he killed Carmen Cubias, 9, and Sammiejo White, 11, in Washington state in 1996 and Anthony Martinez, 10, in California in 1997….

In October, Duncan pleaded guilty in Idaho state court to first-degree murder and kidnapping for the May 16, 2005, hammer slayings of Dylan and Shasta’s mother, Brenda Groene; her fiance, Mark McKenzie; and Groene’s 13-year-old son, Slade.  Prosecutors say he killed them to get the younger children.

If federal prosecutors fail to win a death sentence in the case involving the two younger children, a jury will be chosen in Idaho state court to consider whether to impose the death penalty on the murder counts that Duncan pleaded guilty to in October.  Duncan was charged Thursday in a California state court in Anthony’s death.  Prosecutors there said they also intend to seek the death penalty.

Duncan is a Tacoma, Washington, native who spent most of his adult life in Washington state prisons for sexual crimes against children.  In 2004, he had been arrested for allegedly molesting a 6-year-old boy and attempting to molest another boy in Detroit Lakes, Minnesota.  Authorities say he jumped bail on that charge.

This story has me thinking again about under-explored federalism issues in the debate over the death penalty.  As this case shows, particularly awful murders often provide a basis for the federal government to pursue a capital charge in federal courts.  Wouldn’t it make sense for states to rarely (if ever) pursue capital cases (and not be able to take second bites at the death penalty apple), and for the federal government instead to have primary responsibility for pursuing the death penalty in the most horrific murder cases nationwide?

Significantly, the federal government already tends to dominate the prosecution of the most severe white-collar crimes.  Though they surely could have been be charged with some state offenses, high-profile white-collar defendants like Jeff Skilling and Bernie Ebbers typically face only a federal prosecution.  If this model seems to work for high-profile white-collar crimes, why not also for high-profile murders?