When Matthew Broder, the third son of the late Washington Post reporter and columnist David Broder, was 5 years old, he received a postcard in the mail from his father, who was on a reporting trip in Texas. The card depicted three sad-faced puppy dogs.

“Do you like these puppies?” the father wrote to his boy. “Do you know why they are sad? They are sad because they lost their oil depletion allowance.” The father signed off with “Love” and no doubt returned immediately to his reporting.

The son would come to understand that his father “experienced the world through one lens only — the intersection of politics and policy,” as Matt Bro­der put it Tuesday at a memorial service for his father at the National Press Club.

“When you see the entire world as a classroom,” the son told a packed room of politicians, journalists and readers, as well as a wider audience on national television, “every day brings a new source of joy.”

David Broder traveled 100,000 miles a year, talking to obscure party functionaries and precinct captains and people who rarely even voted, all in search of the facts that would feed the political machinery of Washington.

His column ran in 300 newspapers and he appeared on Sunday morning TV talk shows a record number of times, but he seemed a bit puzzled and awkward when strangers recognized him in airports or on the street.

“He would never go to the Washington parties — he had contempt for that kind of journalist,” said Haynes Johnson, a longtime Post colleague of Bro­der’s who has written political histories based on their shared belief in the power of street-level reporting. “He trusted the voters, and he never tired of hearing from them.”

To Broder, politics could be a sport every bit as enjoyable as his beloved baseball — although not a blood sport. Beneath the superficial game of winners and losers, Broder was always tugging sources and readers back toward what mattered. Which is why his service attracted a row of former and current Cabinet members and senators from both parties, including former defense secretary Donald H. Rumsfeld, who met Broder nearly half a century ago and quickly learned that “he was different from the other reporters. He didn’t play games and he wasn’t always in a rush. He was thoughtful, and he cared about policies and people.”

Said Vice President Biden, who delivered the final eulogy: “He covered Washington with no malice, no sentimentality and no excuses.”

Memorials tend to draw an older crowd and can be given to laments that things aren’t what they used to be. This service included wistful recollections of a time when politics wasn’t as angry or polarized, and when the news business operated at a pace more given to contemplation. But George Broder noted that in the first day after his father died last month at 81, he was the subject of more tweets on Twitter than was Charlie Sheen. And the Facebook page devoted to Broder is a catalogue of tributes from old and new media alike, a compendium of evidence that reporters of all generations saw in Broder the realization of their passion to make journalism democracy’s truth-teller.

“Whatever our own shortcomings,” said Donald E. Graham, chairman of The Washington Post Co. and a eulogist at the memorial, “we could at least look across the room at someone who had” lived up to the ideals that reporters forged at their college papers.

“He was the one who taught me that the best interview is always the one with someone you never heard of,” said Gwen Ifill, moderator of “Washington Week” on PBS and a former Post colleague. Broder was the most generous of co-workers, she said. He would review her copy, and then “he gently pointed out what the news was, so I could put it in the first sentence.”

Broder believed in the power of facts, in the value of reporting that let readers understand the beliefs especially of those with whom they might disagree, and in the necessity of transparency. In his 1973 Pulitzer Prize acceptance speech, he urged journalists to drop the pretense of omniscience and instead say “over and over, until the point has been made, that the newspaper that drops on your doorstep is a partial, hasty, incomplete, inevitably somewhat flawed and inaccurate rendering of some of the things we have heard about in the past 24 hours, distorted, despite our best efforts to eliminate gross bias, by the very process of compression that makes it possible for you to lift it from the doorstep.”

Every year, Broder wrote a column listing the errors and boneheaded or premature judgments he had published over the previous 12 months. He took more pride in that annual exercise than in most scoops.

“He never thought of himself as a pundit,” said Dan Balz, The Post’s national political correspondent, who traveled with Broder to countless chicken dinners and suburban homes. “He believed elections belonged to the voters. . . . He hated frivolousness in politicians. He believed good journalism made the machinery of government work better.”

At political conventions, while editors and TV anchor people retired to the best eateries in town, Broder would slip away to meet with a county commissioner or a state party official he’d heard had a good sense of what was brewing in a battleground community. Or he’d ask a young reporter to join him to knock on doors, where potential voters would find themselves invited to share their hopes and frustrations with a smiling, polite, earnestly curious man in well-worn clothing and what your grandparents would call comfortable shoes.

Broder’s office was a mandatory stop on any tour of The Post’s newsroom, in part because of the breathtaking towers of old documents he’d been collecting since before electric typewriters came along, but mainly because anyone who worked in the place wanted visitors to see where the work was done in its purest, happiest form.

Reporters would bring their parents to meet Broder, as if to drive home the idea that this was work a father or mother could take pride in. Biden said the same sense applied to those Broder covered, recalling how pleased his own father had been to meet the journalist.

Biden said he has always cared about what reporters write about him — “Any politician who tells you otherwise is lying,” he quipped — but in Broder’s case, “I cared what he thought about me. I took it seriously. I learned from him.”

Broder’s son Josh told about the day his father took all four boys to the Senate gallery to explain the inner workings of the body, its committees, amendments and “engineered inefficiency.” When he finished his lesson, Broder announced to his offspring that they would continue the story over in the House, at which point 15 tourists rose to follow along.

His father, in his element, was doing what fathers do best, passing along his passion. “I felt so proud of my father,” Josh Broder said.

The service ended with the audience standing to sing a robust version of “God Bless America.” (It was the second singalong of the event. The first: “Take Me Out to the Ballgame,” Cubs version. Twice.)

As George Broder said of his father: “Decades and decades and decades on the beat, and not a cynical bone in his body.”