A federal appeals panel is poised to rule Thursday on a plea deal for accused 9/11 mastermind Khalid Sheikh Mohammed. Defense lawyers are pushing for the deal to proceed, arguing that Defense Secretary Lloyd Austin's attempt to reject the agreement is flawed.

The plea agreement, reached after years of legal wrangling, would see Mohammed and two co-defendants plead guilty to 2,976 counts of murder in exchange for life sentences, avoiding the death penalty. Family members of 9/11 victims are present at Guantanamo Bay, Cuba, for the proceedings.

Defense attorneys contend Austin's intervention lacks legal grounds. They assert the agreement is valid, and Austin's action constitutes a failure to properly supervise appointed officials. Their legal brief argues against further delay and criticizes the U.S. military's handling of the case.

Conversely, the Biden administration, through the Justice Department, is opposing the plea, seeking to block it. Their rationale centers on the desire to preserve the possibility of pursuing the death penalty. They maintain that the agreement would deprive the government of a public trial and the chance to seek capital punishment.

The 9/11 case has been plagued by procedural and logistical complications for over two decades, marked by pre-trial hearings and ongoing testimony concerning the admissibility of evidence stemming from alleged CIA interrogation methods. The case remains unresolved despite years of legal battles.

The plea deal, presented as the best path towards resolution and justice, was endorsed by military prosecutors, who relayed the agreement to victims' families earlier this summer. However, Austin’s abrupt rejection of the agreement has now triggered a legal showdown.