That's the essence of Obama's challenge on the cusp of the autumn sprint to Election Day. He has to persuade a disappointed electorate - or, more specifically, 50.1 percent of it - that he deserves another chance. He has to buck the sour national mood and persuade enough people that the next four years will be different. He needs to offer specifics on what would be different. He needs to rekindle at least a spark of the old excitement and translate it into a reasonably robust turnout.
It won't be an easy job, not with so many hope-and-changers feeling so let down. Ryan aimed his most resonant speech passage at those voters, notably the young ones: "College graduates should not have to live out their 20s in their childhood bedrooms, staring up at fading Obama posters and wondering when they can move out and get going with life."
Indeed, if Obama does win reelection, his victory margin is likely to be far smaller than it was in 2008. That's very unusual for an incumbent. The last five two-term presidents - George W. Bush, Bill Clinton, Ronald Reagan, Richard Nixon, and Dwight Eisenhower - all won by larger margins the second time around. It would take a small miracle for Obama to match his predecessors, especially in this era of economic stasis.
Actually, given the jobless rate and the restive army of underemployed, it's a small miracle that he is politically buoyant at all. For that he can probably thank the Republicans. According to the latest ABC News-Washington Post poll, Romney has the lowest favorable rating of any nominee since the survey was launched in the early '80s. Plus, Romney's running mate hails from the deeply unpopular Republican House. Plus, the viewing audience for the Republican convention was smaller than the audience for the '08 GOP event, according to the Nielsen folks - and, among viewers ages 18 to 49, Ryan's speech was reportedly eclipsed in the ratings by a cable reality show called Here Comes Honey Boo Boo.
The president's big advantage over Romney - one that he will seek to exploit anew at the Democratic convention - is that swing voters feel they know him. They may be disappointed in him, but they're still persuadable because they instinctively like him. And because they like him, they may be willing to give him the benefit of the doubt when he inevitably says at the convention that, yes, the pace of recovery is slow, but the economic crisis is deeply rooted, and he has been slowed at every turn by an obstructionist GOP.
Never underestimate the power of personal connection. Ronald Reagan, thanks to his likability, garnered millions of votes from people who strongly disagreed with him on policy.
Romney, by contrast, is still something of a cipher. He has Etch A Sketched himself so many times, dating back to the '90s era when he described himself as a "pro-choice progressive," that he can't seem to fill in the frame. He arguably began that process during his Thursday acceptance speech - he talked at length about his admirable parents, and far more reticently about his Mormon faith and Bain Capital tenure - but it's a little late to start now. The guy has been running for president for six years, yet he has failed to define himself; Obama and his Super PAC allies have already seized that opening and defined him in severely unflattering terms, notably as a rapacious vulture capitalist (a label originally affixed to Romney in the winter by Newt Gingrich and Rick Perry).
At the Democratic convention, you can bet that Obama will address the issue of the next four years - not just by sketching out his own plans, but by painting a dire scenario of what Romney-Ryan would do to America in the next four years. Obama doesn't want this election to be a referendum on himself; he's seeking to define it as a choice between the forces of darkness (GOP) and light (him). He and his convention surrogates will start by talking about all the germane Republican material that the Republicans managed to keep off stage.
For instance, one would never have known from watching the GOP convention that Romney and Ryan want to turn Medicare into a privatized voucher program that would force future seniors to pay more money out of pocket; or that the party platform is so extreme in its opposition to abortion that it would compel pregnant rape victims to give birth to their rapists' children (Romney doesn't agree with that plank; Ryan, a longtime House ally of Todd Akin, most certainly does); or that 62 percent of the envisioned spending cuts in Ryan's House budget plan would hit the programs that serve the most vulnerable Americans; or that Romney, in an earlier moderate incarnation, championed a health-reform law that served as the template for Obamacare (Romney, in his acceptance speech, never once mentioned his own gubernatorial achievement).
Democratic convention speakers will pound those themes relentlessly - particularly the large contingent of female and Hispanic speakers, who will seek to reinforce Obama's sizable advantage over Romney among women and Hispanics. (And, presumably, Democratic planners won't cede the stage to a seemingly daft Hollywood celebrity. If you haven't yet seen Clint Eastwood's interminable argument with an empty chair, check it out. What a classic metaphor for today's GOP: an angry old white guy fuming about the Obama of his addled imagination.)
But aside from going negative, Obama's overriding task is to present himself in the affirmative. According to the latest CBS News poll, a mere 35 percent of voters believe he has a clear plan for creating jobs. That stat strikes at the heart of his vulnerability. Banging the alarm bell about the GOP may not be enough to ensure a second term. How would he make things better the second time around? Romney and Ryan posed important questions last week, and the burden is on the incumbent to provide the answers.
Dick Polman can be reached
at email@example.com and followed on Twitter @dickpolman1.