WASHINGTON  — When President Barack Obama stands Tuesday before the mourning children, spouses and comrades of those cut down last week at Fort Hood, he will confront one of the most delicate and painful duties a president undertakes.

Only a president can offer the condolences of a nation. In a moment of crisis and sorrow and anger, only a president can soothe raw emotions, allay fears, elevate a senseless act into a call to action, and offer the assurance that _ as his aides put it Monday _ no stone will be left unturned.

This is by far the biggest test of Obama’s ability to fulfill the role of consoler in chief.

The Fort Hood massacre is the worst single tragedy on his watch. And _ because the victims and the shooter were soldiers, and because the suspect is Muslim and Obama has put such a premium on repairing relations with the Muslim world _ the expectations on him, as commander in chief, are especially high.

“He’s taking a message from the American people as a whole to the victims and their families,” said Martha Joynt Kumar, a Towson University professor who studies presidential communications. “He represents the American people and can express the feelings of pain and tragedy and put it into words.”

Standing before a sea of grieving Americans, acknowledging communal pain, is a task presidents have always undertaken.

George W. Bush, more than most, was called on to flex his empathetic side _ rallying the nation and its allies after the Sept. 11 attacks.

Bill Clinton captured the nation’s dismay after the Oklahoma City bombing. Ronald Reagan offered comfort after the space shuttle Challenger exploded.

The military tragedies seem to have particular poignancy for White House residents.After the bombing of the U.S. embassy in Nairobi, Kenya, in August 1998, Clinton stood before a convoy of black hearses at Andrews Air Force Base, tears streaming down his face.

“We will never know them as you did or remember them as you will: as a new baby, a proud graduate, a beaming bride or groom,” Clinton said.

Then, as presidents do in such moments, he pivoted from an acknowledgement of grief to an effort to seek meaning and inspiration in tragedy:

“We must honor the memory of those we mourn today by pressing the cause of freedom and justice for which they lived.”

An explosion aboard the battleship USS Iowa killed 47 sailors in 1989.

In Norfolk, Va., a week later, the first President George Bush fought back tears as he spoke to mourners.

“Your men are under a different command now, one that knows no rank, only love; knows no danger, only peace,” he said, hurrying through the lines in an apparent race with the tears.

He was so overcome with emotion he abruptly left the lectern without delivering the final lines of his text.

Reagan became tearful at the memorial for the 248 soldiers killed in the crash of a chartered DC-8 in Newfoundland on Dec. 12, 1985, telling families:

“In life they were our heroes, in death our loved ones, our darlings. You do not grieve alone.”

Much of Obama’s efforts Tuesday will be out of public view.

Shortly after arriving at Fort Hood, he and First Lady Michelle Obama plan to meet with families of those killed, at III Corps Headquarters.

They’ll also meet with some of the wounded and their families before the memorial service that starts at 1 p.m. CST.

Before returning to Washington, they’ll stop by Darnall Army Medical Center, where the suspect had worked, to visit other wounded soldiers. 

• Todd J. Gillman