Slate and Doonesbury.com have compiled a list of Doonesbury’s 200 greatest moments. See Slate’s complete coverage of Doonesbury’s 40th anniversary.

This week, Garry Trudeau publishes 40: A Doonesbury Retrospective, a huge and gorgeous collection from the most important, and most hilarious, comic strip of our era. Last week, I interviewed Trudeau by e-mail about the highlights of his four decades with Doonesbury.

Slate:Many great cartoonists of your era—Gary Larson, Berkeley Breathed, Bill Watterson, for example—have hung up the pen, but you seem to have Charles Schulz-ian stamina. How have you avoided burnout?

Garry Trudeau: I suppose it’s just curiosity. I’m still passionately interested in what my fellow humans are up to. For me, a day spent monitoring the passing parade is a day well-spent. And if someone wants to pay me to do that (plus a little drawing), what could be better?

I don’t mean to minimize the stamina issue. Comics are like a public utility: We’re up 365 days a year, and you do have to be built for it. It’s why syndicates now insist on development deals—to find out if a creator has the right temperament. Larson and Watterson set challenges for themselves that were quite different from what I do. Larson created an absurdist universe with no running characters, story lines or topicality. Every morning he stared at a blank piece of paper and developed an idea from scratch, which is exhausting if you have standards as high as Gary’s. Watterson had stories and supporting characters, but the strip was essentially built around a single relationship. Bill built the interactions between Calvin and Hobbes into a marvelous fugue, dense and complex, but it must have been a bear to sustain. I admire both of them for knowing when it was time to get out; it certainly wasn’t obvious to their readers.

Slate:How does the current political era stack up against eras past? Is it more or less funny? Is there more or less material?

Trudeau: I no longer compare them. Each era is the best of times, worst of times. Besides, I’m a pointillist, just working my tiny little piece of the canvas. I’m not so good at perspective.

Having said that, I can tell you that there have been some periods when cartoonists were definitely in clover. Watergate was the perfect subject, because every day brought fresh outrages. Everyone was on his game, and we felt unconstrained, because Nixon’s wounds were self-inflicted. Monica was good for cartooning, but it was only one running joke. Bush’s misrule—accidental war, torture, Katrina, etc.—provoked great cartoons, but there was so much associated tragedy, there wasn’t much fun in it.

Slate: Are there any satirical targets you wish, in retrospect, you’d left alone? Are there any you passed up and wish you hadn’t?

Trudeau: Any obvious satirical target I pass up is usually spared because of a failure of imagination. I just wasn’t able to think of a fresh way in. As to regrets, usually by the time I hone in on someone, they’ve proved indisputably worthy of ridicule. I don’t go cruising for unknown evil outliers.

Slate:Over the years, Doonesbury has been censored, criticized, shrunk, moved around the newspaper. What’s the most memorable or egregious attack on Doonesbury?

Trudeau: Would you settle for the most bizarre? Years ago, I did a series on Joanie Caucus bedding her then-boyfriend Rick Redfern. The week starts with a drawing of Joanie’s empty bedroom. It’s followed by a three-day, dialogue-free tracking shot that takes us out the bedroom window, across town, and into the window of Rick’s bedroom, where Joanie and Rick are intertwined in post-coital bliss. This was too much for many comics editors, and many papers, reluctant to run the foreplay without a payoff, banned the whole week. But the Bangor newspaper had the most unusual solution; in the last frame, instead of the scandalous tableau of Rick and Joanie, the paper ran the day’s weather forecast.

Slate: Where is the comic strip headed in the post-daily-print-newspaper age? Is the medium healthy?

Trudeau: No, we’re all in free-fall together. And Web comics don’t seem to be an alternative, unless you’re uninterested in making a living. There are so many entertainment alternatives to comics now, I’m not sure they’ll be much missed. In their heyday, comics were a dominant force in popular culture, but that’s over.

There’s not much future in being a strip artist now. That’s quite a turnaround in fortunes, because presiding over an established syndicated comic strip used to be the closest thing to tenure that popular culture offered. If I were starting out now, I’d probably continue on the graphic design trajectory I was on before I got sidetracked with comics. Colbert-like TV would be OK, too, except you have to be brilliant. I advise young cartoonists now to get into graphic novels—or head for Pixar.

Slate:Who are your favorite cartoonists, past and present?

Trudeau: I loved Pogo and Peanuts when I was growing up, but Jules Feiffer was probably my strongest influence. The stripped-down drawing style, lack of balloons, and stacks of dialogue all conveyed a radical notion: Here be ideas. And immediacy. Feiffer was actually a master draftsman, but he made the art looked tossed off, like he was doing it on the subway on his way home from sessions with his shrink.

Slate: You’ve said that you don’t spend time with Doonesbury characters in your off-hours. What do you mean by that?

Trudeau: I just meant that the only time I ever think about my characters is when I’m consciously working. Coming up with ideas is really hard—they don’t spontaneously pop into my head while I’m cutting vegetables.

Slate:How do you “report” the strip? If you’re covering the war or a political scandal, how do you research it? If you want to capture how a 22-year-old speaks, what do you do?

Trudeau: I guess I just listen to my kids and their friends, but not in any conscious way. By now, I have a fairly practiced ear. As to research, given my deadlines, it’s unavoidably perfunctory. But it’s a comic strip, authoritative about nothing, and I can usually get by with verisimilitude, what Colbert calls truthiness.

There are exceptions to that, of course. To prepare for some stories, I’ll read books, search the Web, interview people, travel—all the things you might expect. I went with President Ford on his China trip for the Honey/Duke story, spent a week in Scotland for Bernie’s Loch Ness expedition, and interviewed Viet Cong veterans in Saigon for B.D.’s return to Vietnam. Most weeks, though, I’m hunkered down in the studio, just grabbing what I need from Google, the Swiss Army knife of investigative cartooning.

Slate: In 1977, you made a Doonesbury TV special with the celebrated animation team of John and Faith Hubley. But there have been no follow-ups, either for TV or the movies. Why not?

Trudeau: Well, I was game at the time, but the network felt the ratings were disappointing. We had an audience of 21 million. I’m not kidding. Different era. The other reason is that I don’t want to spend all my discretionary time on Doonesbury. I do other work in TV and film, and it’s nice to have a break from the strip.

Slate: Who’s the hardest politician to satirize, and why?

Trudeau: Believe it or not, Obama’s very tough for business. The contradictory characterizations of him as fascist or socialist only serve to confirm the truth—he’s a raging moderate. And satirists don’t do well with moderates, especially thoughtful ones. In addition, Obama rarely makes gaffes and has no salient physical or temperamental features. And sinking popularity isn’t a critique. Even SNL’s main rap on him is his unflappability, hardly a vice in a world leader.

Slate: How are baby boomers admirable, and how are they awful?

Trudeau: Baby boomers are at their awfulest when they are discussing themselves, and at their most admirable when they refrain. I try to be admirable.

Slate:Will you ever stop writing Doonesbury?

Trudeau: I’m not sure the choice will be mine to make. I’m standing in quicksand. But I don’t have any plans to retire in the near future.

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