It was another one of those weeks in the capital when our leaders debated matters crucial to the survival of American civilization.

Did President Obama try to upstage the Republican presidential debate by asking to address a joint session of Congress that same night? And did Speaker John Boehner “diss” the president, and the presidency, by denying him that slot?

Tempted though I was to weigh in on this important matter, I decided instead to head over to the Smithsonian’s American history museum, to preview a small but immensely powerful exhibit to mark the 10th anniversary of the Sept. 11 attacks.

There, displayed for the first time, are sacred relics of 9/11: the crumpled piece of the fuselage where the American flag had been painted on the Boeing 757 that crashed in a Pennsylvania field; a flight-attendant call button from the plane, a window shade, landing gear strut, and logbook with the pages intact. The exhibit is simple and raw, without glass or showcases. Some dried mud caked on an airplane seat belt was flaking off onto the tablecloth.

Nearby is the door from a firetruck crushed at ground zero and the beeper of a man who died in the South Tower. There’s a Pentagon clock frozen at about the time American Flight 77 struck the complex, and the phone on which Ted Olson received the last call from his wife on the doomed plane. Most poignant, perhaps, is the postcard from another passenger, written to her sister the day before the crash to give the address of a new home in which she would never live.

The spare exhibit brought back the horror of that time. But it also reminded me of the pride in what followed, the national unity and sense of purpose. The warm feelings didn’t last long, of course, destroyed by Iraq and the politicization of homeland security.

By now, we have lost all sense of purpose in politics, alternately distracted by Sarah Palin’s bus tours, Anthony Weiner’s private parts, David Wu’s tiger suit, Donald Trump’s birth certificate campaign, and Dick Cheney’s broadsides.

The president, whose uncertain trumpet has ceased to rally even his own troops, contemplated his long-delayed jobs agenda while lounging on Martha’s Vineyard last month. His leading Republican rival talks of treason and secession. Another challenger arranges the quadrupling of his California mansion (his defense: He’s only doubling the living space). Lawmakers play games with the debt ceiling and wound the nation’s credit rating but can’t agree on anything to put Americans back to work.

The political irrelevance, in other words, is like that of early September 2001. We spent those days amusing ourselves with Gary Condit and shark attacks. The president spent that August on a record-long ranch vacation. The biggest issue: stem-cell research. Warnings about Osama bin Laden were ignored while the administration obsessed over rewriting a missile treaty with Russia.

What will it require to end the drift this time? A depression? Another attack? Or is there a less painful way to regain national purpose?

“For most people,” curator David Allison told me as I toured the Smithsonian exhibit, “Sept. 11 is only a media event.”

The exhibit is a modest attempt at changing that, taking that day’s ruins out of storage and rekindling memory. The lucky few who see the exhibit during its short run will be reminded that there are things more important than whether the president addresses Congress on a Wednesday or a Thursday.

Consider the simple postcard, written by Georgetown economist Leslie Whittington to her sister and brother-in-law, as Whittington, her husband and their 8- and 3-year-old daughters headed off to Australia for her sabbatical. The card, postmarked Sept. 12 at Dulles Airport, must have been mailed just before the family boarded American Flight 77. The note says, in its entirety: 

9/10/01 

Dear Sara & Jay, 

Well, we’re off to Australia. When we return we will have a new address (as of 11/30): 

xxxxxxxxxxxxxx

xxxxxxxxxxxxxx 

We don’t know our phone # yet. While we are in “Oz,” email will work best for contacting us: whittinl@georgetown.edu. 

Love, Leslie, Chas, Zoe & Dana 

I thought about Sara receiving that postcard from her dead sister, and about those little girls who never made it to their new house — because of 19 evil men and a government distracted by less-important things.

Then I went out onto Constitution Avenue, where, across from the museum, a bus labeled “Extreme Makeover: Home Edition” had just parked.

Dana Milbank is a columnist for The Washington Post Writers Group. He can be contacted at:

danamilbank@washpost.com