Is it legal for the US to livestream the Fort Hood shooter's execution? - explainer

The Pentagon said on Thursday that it would livestream the firing squad execution of the man who killed 13 people at the Fort Hood military base in 2009, raising questions about the legality of the unprecedented announcement.

Here's what US law says about public executions and death by firing squad.

Is death penalty by firing squad legal in the US?

Yes. The US Supreme Court said in a unanimous 1879 decision that execution by firing squad is not "cruel and unusual punishment" prohibited by the Constitution.

The justices last year cleared the way for South Carolina to carry out its first execution by firing squad in decades.

Five states currently allow executions by firing squad: Idaho, Mississippi, Oklahoma, South Carolina, and Utah. The Trump administration earlier this year said it would allow execution by firing squad in the federal prison system.

The US Army also once regularly carried out executions by firing squad of US soldiers found guilty of desertion or other offenses. Hundreds of US soldiers were sentenced to death during the Civil War from 1861 to 1865.

Under the Uniform Code of Military Justice, the president is the only person who can approve a death sentence for a member of the US armed services. President Donald Trump, on October 5, signed off on the Pentagon's plan to execute the Fort Hood gunman, Nidal Hasan, a former Army psychiatrist.

Can executions be broadcast?

Executions in the US were once public spectacles, but in the last century have been carried out in correctional facilities away from the public eye.

In 1936, a man convicted of rape was hanged in front of thousands in Owensboro, Kentucky, while the following year, hundreds watched a public hanging in Missouri.

A US law prohibits the recording or broadcasting of executions in the federal prison system. But military regulations have not applied that same prohibition to military executions. Hasan was convicted of premeditated murder by a military jury in 2013, following a court-martial trial.

State laws regulate who can witness executions, generally limiting access to authorized officials, family members, legal counsel, and a handful of media representatives.

Courts have long rejected lawsuits brought by media organizations seeking broader public access to executions.

In 2001, a judge denied a request by an internet company to livestream the lethal injection execution of Timothy McVeigh, an anti-government militant who bombed a federal building in Oklahoma City in 1995, killing 168 people. The Justice Department did provide a restricted, closed-circuit television broadcast exclusively for survivors of the bombing and victims' families.

Could Hasan challenge his execution in court?

While Hasan has exhausted his direct appeals within the military justice system, he can still challenge his underlying conviction and sentence in the federal civilian court system.

Such a challenge, known as a federal habeas corpus proceeding, provides another layer of review before a death sentence is carried out.

Even if unsuccessful, such a challenge could stall the execution, potentially for years. Hasan's execution is currently set for December 3.