Accused Sept. 11 mastermind Khalid Sheikh Mohammed showed no mercy and deserves none today.

It’s that simple. His military tribunal has become a joke and Defense Secretary Pete Hegseth should order the trial to commence immediately and have it broadcast live. The loved ones of the nearly 3,000 people who were murdered that day deserve nothing less.

Time, in this case, will never heal old wounds.

People jumped to their deaths rather than be burned alive in the Twin Towers on 9/11; passengers on the hijacked jets were slaughtered. It’s already too late to send a message to terrorists that justice will be swift if you attack America.

So the only answer is a trial to end all trials.

Expose every last devious aspect of the terror attack — all the countries that looked the other way and the spy agencies that failed fellow Americans.

“We cannot allow this chapter to be closed without a full public trial,” Brett Eagleson told the Herald Monday. “America deserves it and the families of nearly 3,000 Americans who watched their loved ones murdered on TV deserve a trial. Without a trial there is simply no justice.”

Eagleson was 15 years old when his dad, Bruce, died when the Twin Towers collapsed in New York City. His father was in charge of the retail shops in the basements of the World Trade Center and didn’t leave his employees to die alone.

We all know the heroism, or damn well should, and now the Trump administration must exhibit that same courage and put the sins of Khalid on the stand for the world to see.