How Bill Clinton ad-libs his way to a winning speech David Kusnet: Bill Clinton often speaks without relying on a teleprompter He says Clinton has the ability to come up with memorable phrases on the fly Kusnet: In DNC talk, he played the role of public policy prof but used accessible language Editor's note: David Kusnet was President Bill Clinton's chief speechwriter from 1992 through 1994. He is the senior writer and a principal at the Podesta Group, a government relations and public relations firm. (CNN) -- Twenty years ago, I was standing next to a teleprompter operator in the cavernous Cobo Hall in downtown Detroit. Presidential candidate Bill Clinton was addressing the Detroit Economic Club, and I was guiding the teleprompter operator through his prepared text. Drafted during an all-nighter -- one of many we'd pull during his campaign and presidency -- the speech presented his economic program in exhaustive detail. But, after ad-libbing lines from the beginning, Clinton extemporized an exhaustive explanation of German apprenticeship programs for skilled workers in manufacturing. By the time Clinton concluded his tutorial on job training programs, the teleprompter operator asked me where to start scrolling the remainder of the prepared text. "Don't worry," I told him. Clinton will do just fine. Analysis: Clinton speech hit Obama's marks David Kusnet In his speech at the Democratic National Convention last night, Clinton still did just fine, just as he's done in so many speeches where he's treated his prepared text the way jazz greats soar from the sheet music. By one account, the former president spoke for 48 minutes and 5,895 words, while his prepared text, which had been distributed beforehand to the media, was only 3,136 words. No wonder, when asked about her husband's speech, Secretary of State Hillary Clinton said she was looking forward to comparing the "as prepared" and "as delivered" texts. Reviewing each version, it's clear that the same person wrote both -- the same president who improvised 20% of his first State of the Union address and explained his health-care plan from memory to a joint session of Congress after the teleprompter displayed the text of an earlier speech. Clinton's improvisations are instructive because they show how the nation's most popular political figure (69% approval rating, according to a USA Today/Gallup poll) still serves as extemporizer-in-chief. While most speakers ad-lib anecdotes, Clinton also explains complex issues off-the-cuff. A sampler of Clinton's improvisations: Zinger of the Week: When Clinton zapped Republican vice presidential nominee Paul Ryan on Medicare spending reductions, "It takes some brass to attack a guy for doing what you did," that line wasn't even in the prepared text. Bashing Brutus: In Shakespeare's Julius Caesar, Mark Antony's funeral oration for the slain statesman skewers his rival by saying simply that Brutus is an "honorable" man. In improvised remarks, Clinton uses the same time-honored technique, describing the Republicans: "They convinced me they were honorable people who believe what they've said, and they're going to keep every commitment they've made. We've just got to make sure the American people know what those commitments are. Improvised Uplift: Clinton also effortlessly extemporized eloquent sayings that other public figures and their staffs might write and revise for several drafts: "Democracy does not have to be a blood sport." And "So far, every single person who has bet against America has lost money." Public Policy Professor: If you think the auto mileage standards are complex, listen up: "No matter what the price [of gas] is, if you double the mileage of your car, your bill will be half of what it would have been." Softening the Blow: Clinton's conversational tone makes it easier for him to persuade undecided voters. As did Ronald Reagan, Clinton introduced his arguments with folksy asides. Before criticizing today's Republicans, Clinton began by ad-libbing: "Now, there's something I've noticed lately, You probably have, too." Historian-in-Chief: Concluding his speech, Clinton reminded his audience that America -- and, by inference, its presidents -- have displayed remarkable resilience. Departing from his prepared text, Clinton added this anecdote about the first president: "People have predicted our demise ever since George Washington was criticized for being a mediocre surveyor with a bad set of wooden, false teeth." As president, Clinton would refer to most of his formal remarks not as speeches but as "talks," subtly reminding his staff that he wanted to address Americans as adults to be persuaded, not an audience to be manipulated. By improvising so often, and using so few freeze-dried and focus-grouped applause lines, Clinton continues to keep his speeches fresh, friendly and factual in the hope that his listeners will open their minds to what he says. Yes, the Comeback Kid has made more farewell tours than Frank Sinatra. As with Old Blue Eyes, he does it his way. The opinions in this commentary are solely those of David Kusnet.