WASHINGTON — When he addresses a memorial for the Tucson shooting victims, President Obama -- like Ronald Reagan after the Challenger explosion, Bill Clinton after the Oklahoma City bombing and George W. Bush after Sept. 11 -- will stand before a nation that is taking stock of him in a crisis.
The president must try to comfort the Tucson community and the nation, mourn the dead, call for unity and healing, and yet avoid saying anything Wednesday that would appear to politicize the event or use it to overtly boost his standing.
At its best, a speech such as this should emotionally connect Americans to one another, and to him. At its worst, it could be a lost opportunity to demonstrate the kind of personal leadership Obama's predecessors summoned at moments of national tragedy.
"This is an opportunity for him to more fully express his leadership of the country, hopefully to maybe turn down the heat on the debate and bring the country together," said Douglas B. Sosnik, a Clinton White House political director. "He can say that it's OK for people to disagree, but how they express it is important, because words matter and they have implications. This is a moment for that."
One painful question for many Americans is whether the nature of political discourse somehow brought on this tragedy. Television, radio and Internet conversations about the shooting roil with theories, alternately blaming the left wing and the right wing for provoking the alleged shooter, and sometimes blaming them both.
A CBS News poll suggests that nearly 6 in 10 people think that heated political rhetoric is not to blame for the tragedy. But the fact that so many people even have an opinion suggests a currency to the question. Obama may eventually need to address it.
"He's not speaking for one party or another when he deplores violence and calls for civility," said Michael Waldman, who was Clinton's chief speech writer during much of his second term. "That's speaking for the country, but he doesn't want to overdo it. This is above all else a private tragedy for the people involved."
White House aides said Obama would steer clear of politics at the event, which begins about 5 p.m. PST. They said he would focus almost entirely on the people, families and the community affected by the shooting.
Peter Wehner, who helped craft Bush's remarks at the post-Sept. 11 national prayer service, warned that there were many "tripwires out there, and this debate is hot." The conservative media will be eager to push back if Obama is perceived as "trying to rap the knuckles of conservatives or trying to draw some deeper political meaning from this, rather than moral."
Obama "has got a chance to bring the country together and recapture what was attractive during the campaign to a lot of people, which is the post-partisan, transpolitical persona he had," Wehner said.
A challenge for Obama will be "to show real human warmth," Wehner said. "He's actually had a hard time doing that. He needs to be very careful that he doesn't come across as cool and detached."
Obama has led the nation in prayer at least twice before, after the massacre at Ft. Hood, Texas, in 2009, and after 29 miners died last spring in a West Virginia explosion.
At that memorial service, Obama offered words of comfort by speaking of those who perished.
"Most days they would emerge from the dark mine, squinting at the light," he said of the miners. "Most days, they would emerge, sweaty, dirty, dusted with coal. Most days, they would come home. Most days, but not that day."
The words were delivered in Obama's earnest but dispassionate way, a trademark style that bewilders some observers of the former law professor. Friends say Obama is uncomfortable exposing his emotions in public.
But on Wednesday he must take stock of a different kind of tragedy -- an attempted assassination of a member of Congress and the killing of a federal judge and five others -- when he takes his place at a service of prayers, poetry and blessings.
"The president will have to strike the right tone. He will not want to politicize something that is not overtly political," Waldman said. "He is there to comfort families and the community. When he says that there is something special about a member of Congress meeting the citizens and being able to do so without fear of violence, that's not political -- that's speaking for the country."
Setting that as a goal and pulling it off are two different things. Clinton has weighed in with advice. In a BBC interview, the former president said the House of Representatives should take the lead in changing the tone and tenor of the country's political discourse.
"No one intends to do anything that encourages this sort of behavior," Clinton said while on a trip to Haiti. But political rhetoric "falls on the unhinged and the hinged alike."