The lead military attorney prosecuting Khalid Sheikh Mohammed, Walid Muhammad Salih Mubarak Bin 'Attash, Ramzi Binalshibh, Ali Abdul Aziz Ali, and Mustafa Ahmed Adam al-Hawsawi argued the conspiracy charges could not be issued as "stand-alone offenses" against the accused, according to a Pentagon release.
However, the tribunal denied the request, ruling that there was "substantial uncertainty" whether the Hamdan reversal could apply to the 9/11 detainees.
Along with the conspiracy counts, the accused plotters also face a number of other charges connected to their involvement in the planning and execution of the 9/11 attacks on the World Trade Center and Pentagon.
The defendants have been housed at the U.S. detention facility at Guantanamo Bay, Cuba since the beginning of the military tribunal proceedings.
The appeals court in 2008 ruled that Hamdan's role as al Qaeda leader Osama bin Laden's personal driver and bodyguard in 2001 did not constitute "an international war crime." The Yemeni national was deported back to his home country before the appeals court could deliver their decision.
At the time of his deportation, Hamdan had spent 66 months in U.S. custody.
Martins, who is heading up the case against the remaining 9/11 conspirators requested the conspiracy charges be dropped, based on the appeals court ruling on the Hamdan case.
Military officials declined the request to drop the conspiracy counts because the activities allegedly taken by the conspirators were viewed as "as a chargeable offense" under current statutes governing international war crimes.
--updated at 4:35pm