WASHINGTON (AP) _ For the first time since winning the White House, President Barack Obama is being called on to heal the wounds of a national tragedy, a role that can help shape a presidency at a time of national tragedy.

Obama headed Tuesday to Fort Hood, Texas, the site of the worst mass shooting ever on a military facility in the U.S. An army psychiatrist, Maj. Nidal Malik Hasan, is accused of the rampage that left 13 people dead and 29 wounded before the gunman was shot by civilian police.

Obama privately consoled families of those killed, and then publicly paid respects at a memorial service watched by American troops around the world. He and first lady Michelle Obama also visited wounded troops in the hospital before returning to Washington.

His agenda Wednesday: another war council meeting on Afghanistan, and laying a Veterans Day wreath at Arlington National Cemetery.

This is Obama’s time to take on the healer-in-chief role that can help shape a presidency at a time of national tragedy.

Obama’s predecessor, George W. Bush, governed during the worst terrorist attack on American soil, the most crippling natural disaster in U.S. history, a space shuttle explosion, a shooting rampage at Virginia Tech, a tornado that wiped away a Kansas town, a bridge collapse in Minnesota, Midwestern flooding and California wildfires. Each response affected his standing, for better or worse, in a country that expects its president to be empathetic and clearly in charge.

History is full of other examples. Bill Clinton helped rebuild his troubled presidency with the way he reacted to the Oklahoma City bombings.

In this case, Obama has sought his own balance.

He has promised a full investigation of the Fort Hood shootings but has said little about it as police search for a motive. He has praised religious diversity in the military, trying to offer calm as questions loom about whether the alleged shooter had ties to extremist Islamic ideology. And he has delayed a trip to Asia to attend the memorial service.

The mass killing shook the nation even more because it happened in a presumed haven of U.S. security. The suspect himself is a soldier, Maj. Nidal Malik Hasan. Authorities say he fired off more than 100 rounds before a civilian police officer shot him. He survived and is in stable condition.

It wasn’t even two weeks ago that Obama stood in the dark of night at Dover Air Force Base in Delaware, honoring the remains of 18 troops killed in Afghanistan. Now he will lead the mourning for 13 men and women who were working in the one place, as Obama put it, that “our soldiers ought to feel most safe.”

Among those killed at Fort Hood were 21-year-old Pvt. Francheska Velez, who was pregnant and preparing to return home after a recent deployment in Iraq. And Spc. Jason Hunt, a 22-year-old who served in Iraq and was married two months ago. And Maj. Libardo Caraveo, 52, who was headed to the war zone in Afghanistan.

Obama’s presence alone will be meaningful to those hurting at Fort Hood, said Kevin Sullivan, who served as Bush’s communications director.

“It sends a message that he understands this is a national moment,” Sullivan said. “But what really matters is that the president is able to provide some comfort to the sons and daughters and husbands and wives of the victims. That’s ultimately why he’s going. He’s saying, ‘The whole country grieves for you.”’

First lady Michelle Obama will be at the president’s side.

At least 3,000 people are expected to attend the memorial service. They include the families of the 13 victims, as well as some of those wounded and their families, said Lt. General Robert Cone, the post commander. The event is open to the public.

Preparations for the president’s visit began late Sunday, when the Army started erecting a giant wall of metal shipping containers stacked three high for hundreds of yards. The temporary walls have created an L-shaped outdoor theater on a large grassy field at Fort Hood, the nation’s largest military installation.

Cone said the service should help the post take a step toward normalcy.


Associated Press writer Jeff Carlton at Fort Hood, Texas, contributed to this report.

Pictured above is President Obama, assisting a wounded veteran.