The 78-page motion and its 840-page appendix were the defense team's most dramatic attempt yet to spare their client from a death sentence if he is convicted.
Lawyers Peter D. Greenspun and Jonathan Shapiro used traditional arguments based on morals and decency, as well as newer arguments drawing on wrongful convictions and new DNA-testing technology.
"To endorse the death penalty as a constitutionally just and proper punishment for convicted criminal defendants, one must necessarily endorse the constitutional propriety of executing innocent people or those convicted by improper or imperfect means," the defense attorneys wrote.
His alleged co-conspirator, teen Lee Boyd Malvo, will be tried first for the killing of Linda Franklin in Fairfax County.
While six of the 10 killings attributed to the pair occurred in Maryland, the Justice Department decided they would first be tried in Virginia, where the death penalty would be easier to obtain, especially for Malvo. Maryland does not allow the execution of juveniles.
That point was not lost on Muhammad's lawyers, who wrote that the "politicization of the application of the death penalty in this case further highlights the inherent unfairness and unreliability of the system."
The defense team had previously tried - and failed - to rule out the death penalty on narrower grounds.
Last month they argued that Malvo's alleged statements to police that he was the trigger-man in some of the killings makes Muhammad ineligible for death.
Their lengthy motion yesterday was an impassioned treatise against the death penalty itself.
The lawyers relied on a study of 5,760 capital cases by Columbia University Law School Professor James Liebman, who found 68 percent of the death penalty convictions were "seriously flawed" and overturned by higher courts.
"In a system where two-thirds of all verdicts are known to suffer serious error, it is an absolute certainty that innocent people have been tried, convicted and wrongfully executed by the state," Greenspun and Shapiro wrote.
In other motions yesterday, they asked for money to hire a jury consultant and revealed their proposal for a questionnaire to be filled out by potential jurors, which includes asking their views on the death penalty.
The next hearing in the case is set for Aug. 18.
