The debate over where to try Khalid Sheikh Mohammed and his four alleged Sept. 11 co-conspirators is defined by sharp disagreement over the legal rights of accused terrorists and the relative strengths and weaknesses of civilian and military commission systems.

The Obama administration is nearing a decision on where to hold a terrorism trial that was once slated for New York City and officials are struggling to develop a clear rationale for sending some detainees into federal court, keeping others at the Guantanamo Bay detention facility for trial by military commission, and detaining others without any trial at all.