In Arizona tonight, Barack Obama’s healer-in-chief speech may well sound something like this: “Today is a day for mourning and remembering. For the families of the (deceased), we cannot bear, as you do, the full impact of this tragedy. But we feel the loss, and we’re thinking about you so very much. We share your grief, your pain is unimaginable, and we know that. We cannot undo it. Our words seem small beside the loss you have endured. You have lost too much, but you have not lost everything. And you have certainly not lost America, for we will stand with you for as many tomorrows as it takes. My fellow Americans, a tree takes a long time to grow, and wounds take a long time to heal. But we must begin. Those who are lost now belong to God. Some day we will be with them. But until that happens, their legacy must be our lives. It is said that adversity introduces us to ourselves. This is true of a nation as well. In this trial, we have been reminded and the world has seen, that our fellow Americans are generous and kind, resourceful and brave. Nothing ends here; our hopes and our journeys continue.”That passage is actually an amalgamation – in today’s parlance, a mashup. I pulled those lines from three presidential addresses: President Reagan, responding to the Challenger space shuttle explosion in 1986; President Clinton, eulogizing in Oklahoma City in 1995; and President Bush, speaking at the National Cathedral shortly after 9/11.The point is, there’s only so much that any chief executive can say in the wake of serious tragedy. The best addresses have said it.Granted, when Americans are shocked and grieving, they expect the president to offer soothing eloquence, to exude empathy, to invoke the purported better angels of our nature. Obama is sure to follow the aforementioned speech template (even though, on the empathy front, he doesn’t go in for Clintonian lip-biting). Symbols are indeed important, and in such moments a president is called upon to act as our symbol of unity (at least for those Americans who view this particular president as a legitimate symbol). But let’s not inflate expectations, and somehow assume that whatever he says will cure our ills and transform us as a people.I keep hearing, from the Washington press corps, that “the stakes for Obama’s address are high,” as if we’re all supposed to view the Arizona speech through the narrow prism of his current political standing, mindful that Clinton’s comeback in the aftermath of his ’94 midterm shellacking supposedly began with his response to the Oklahoma City bombing. And, after all, check out the parallels: Clinton’s Gallup job approval rating in early ’95 was 46 percent; Obama’s, last month, was 46 percent. But the stakes-are-high narrative strikes me as classic Washington myopia. This event is about a death toll, not the Gallup poll.Yes, if Obama strikes the right chords (and who among us doubts that he will?), he can avail himself of some collateral benefits. The occasion requires that he seize the center and speak, albeit glancingly, about the importance of compromise, consensus, and civil postpartisan dialogue. Those happen to be some of his favorite themes anyway; in a University of Michigan commencement speech last spring, he said: “Vilification and over-the-top rhetoric closes the door to the possibility of compromise. It undermines democratic deliberation.”The Arizona memorial service is not the right venue to flesh out such themes in detail. But we should hardly be surprised to hear Obama briefly lament the climate of hatred that imperils democracy – witness the Saturday morning meet-and-greet session that was so tragically truncated – and he’ll undoubtedly plead, yet again, for a lowering of voices. For what it’s worth, Obama can potentially connect with the divided electorate by owning this bring-us-together moment. It’s in the job description; at times like this, only a president has the bully-pulpit clout to frame the tone and drive the discourse ( these days, at least for one news cycle).But this memorial service is not a political event. It’s about the young girl who wanted to meet her congresswoman; it’s about the judge who stopped by after church to say hello; it’s about the other felled citizens who felt instinctively safe outside their neighborhood Safeway. We’ll undoubtedly parse whatever Obama says, just as Reagan and Clinton and Bush were parsed in their moments, but ultimately, this service is not about him. He’ll keep it brief, knowing that a more suitable occasion awaits, later this month on Capitol Hill, when he can expound on the state of our disunion.