[This is an updated version of an earlier post.]

Bill Clinton is typically described as the empathetic, feel-your-pain guy. But his greatest political skill may be as a formulator of arguments -- the explainer in chief.

At the Democratic National Convention on Wednesday night, he did not disappoint, boiling down Mitt Romney's case to one sentence: "In Tampa," he said, "the Republican argument against the president's re-election was actually pretty simple, pretty snappy. ... 'We left him a total mess, he hasn't cleaned it up fast enough, so fire him and put us back in.'"

And he cast the philosophical differences between the parties just as crisply. Republicans, he said, believe in "a winner-take-all, you're-on-your-own society," while Democrats seek "a country of shared opportunities and shared responsibility -- a we're-all-in-this-together society."

That Clinton, the cheerful political educator, played such a central role at this conclave reflected the extent to which it should be seen as a three-day tutorial designed not only to defend President Obama's economic stewardship but also to advance a view of government for which, over the past 40 years, Democrats have often apologized.

And off Clinton went in his classic style: the "country boy from Arkansas," as he called himself, who was rambling yet focused and methodical, embroidering his text with folksy asides, getting the crowd to cheer even budget numbers and statistics. He went long, and they wanted him longer.

It's ironic that the 42nd president played the co-professor with Obama in this advanced government class. Clinton is associated with a determined effort to distance his party from its past, and when Clinton pronounced in 1996 that "the era of big government is over," it was taken as a concession to the new conservatism that swept to control of Congress just over a year earlier.

But Clinton's rhetorical move was more tactical than fundamental. He never stopped believing in the power of government. And with Republicans putting forward the most emphatically pro-business, anti-government agenda since the Gilded Age, he and his fellow Democrats now feel an urgency to assert the state's positive role.

Thus, one of the most applauded lines of the convention's first night came from Massachusetts Gov. Deval Patrick: "It's time for Democrats to grow a backbone, and stand up for what we believe." Rarely has a party so fully embraced a declaration that implied its own past spinelessness.

Clinton, once known as the author of a strategy of "triangulation" between the parties, was among the speakers who answered Patrick's call. He assailed Romney and Paul Ryan for falsehoods on welfare and Medicare, dismantling one Tampa argument after another. Offering a vision of "shared responsibilities, shared prosperity, a shared sense of community," he stoutly defended the president's health care law, his student loan reforms, his auto industry rescue, his commitments to community colleges and job training, and his budget proposals.

He joined Elizabeth Warren, the financial reformer who is the Democrats' Senate candidate in Massachusetts, in presenting government not as an officious intermeddler in people's lives but as an ally of families determined to help their children rise. Government, Warren said, "gave the little guys a better chance to compete by preventing the big guys from rigging the markets."

And there lay the other stark contrast between the Tampa Republicans and the Charlotte Democrats. Building their convention around an out-of-context quotation from the president, Republicans offered a counter-theme, "We built it."

But the message of Tampa often came off more as: "We own it." Working people and the dignity of labor receded into the shadows cast by the investors, entrepreneurs and business leaders.

The Democrats' version of the American dream is built of different stuff, on individual and family struggle. Republicans may cast themselves as champions of "family values," but Democrats here -- notably Michelle Obama and the keynoter, San Antonio Mayor Julian Castro -- spoke far more about upward mobility as a family enterprise.

Yet Democrats know that the president still carries the burden of high unemployment and sluggish growth. And that is why he called in as a witness the man who presided over years that voters remember as an all-too-brief journey through the economic promised land.

Obama, Clinton testified, "inherited a deeply damaged economy, he put a floor under the crash, he began the long hard road to recovery, and laid the foundation" for a new economy whose positive effects they would soon feel. "I believe this with all my heart," he said, devoutly hoping that his heart-to-heart talk would get Americans to believe, too.

(c) 2012, Washington Post Writers Group