Expect the bigger bounce for Romney

Each party convention usually produces a bounce in the polls of 6 to 10 points, though they often cancel each other out. But this year there will be different. The Republicans will gain much more from their convention than the Democrats will from theirs. This year, there will be no offsetting bounces; the advantage will be Romney’s.

The parties go into their respective conventions with very different tasks in mind. The Republicans need to use their conclave to wipe off the grime with which Obama’s campaign has largely succeeded in covering Mitt Romney. The Democrats will want to continue to besmirch both the opposing party and its nominee and to use the convention to sully the image of the newly minted GOP vice presidential candidate, Paul RyanPaul RyanRyan: Graham-Cassidy 'best, last chance' to repeal ObamaCare Ryan: Americans want to see Trump talking with Dem leaders Overnight Finance: CBO to release limited analysis of ObamaCare repeal bill | DOJ investigates Equifax stock sales | House weighs tougher rules for banks dealing with North Korea MORE.

But the four-day format of dramatic speeches, films and delegate interviews has historically been very good at fleshing out the biography of the candidate. It has not, however, been historically effective as an instrument of negative campaigning. So the Republicans are much more likely to achieve their goals than Team Obama is.

History is full of successful biographic conventions. Even when the candidate’s biography — as elaborated at the convention — turned out to be a mixture of lies and exaggerations, when the convention was gaveled to a close, the American people largely accepted it, if only for the moment, as accurate. Frequently, the warm biographic glow spawned by the convention went away as the campaign wore on, but the fact is that the convention had established the candidate’s biography, even if only temporarily.

In 1984, Walter Mondale left his convention with his image glowing after selecting Geraldine Ferraro for vice president. Through September, her image was in tatters, but it worked at the convention.

In 1988, Michael Dukakis sold his immigrant heritage and surged to a 17-point lead. He lost it in a tangle of hot-button issues, but the convention succeeded. 

At the same time, George H.W. Bush, with an assist from speechwriter Peggy Noonan, convinced us that he was “a quiet man who heard the quiet voices” as he searched for “a thousand points of light.” 

In 1992, the glow of the comeback kids — Bill ClintonBill ClintonGOP rep: North Korea wants Iran-type nuclear deal Lawmakers, pick up the ball on health care and reform Medicaid The art of the small deal MORE and Al GoreAl GoreStop the loose talk about hurricanes and global warming Parties struggle with shifting coalitions OPINION | Midterms may provide Dems control — and chance to impeach MORE — was firmly established and their generational theme well-articulated. 

In 1996, Elizabeth Dole framed her husband Bob’s biography in an Oprah-esque narrative that brought the candidate the only dash of warmth in his long political career.

In 2000, George W. Bush sold the idea that he was a “compassionate conservative” with a heavy emphasis on education.

In 2004, Lt. John KerryJohn Forbes KerryBringing the American election experience to Democratic Republic of the Congo Some Dems sizzle, others see their stock fall on road to 2020 The Hill's 12:30 Report MORE emerged as a Vietnam war hero, only to be swift-boated in the weeks to come.

And, in 2008, Obama presided over the mother of all biographic conventions as his shining star burst forth over an unsuspecting and gullible country.

And so the 2012 Republican convention will probably succeed in introducing Romney and Ryan and in covering them with accolades, which will help to offset the pounding to which Obama has subjected them.

Will Obama succeed comparably in his negative convention mission? Not very likely.

Conventions aren’t good at throwing negatives. The only success that comes to mind was the 1964 assault on Barry Goldwater led by Hubert Humphrey.

The 1992 Republican convention failed to hurt Clinton. Despite wall-to-wall negatives aimed at both Clintons (more Hillary than Bill), it was the only convention in recent times not to produce any bounce for its candidate. Clinton had trailed badly — often running third to Bush and Perot — until his convention, but  he never relinquished the lead thereafter.

Democrats will be so focused on the negative — exploiting Todd Akin’s remarks, attacking Ryan’s budget, ripping Republican Medicare proposals and talking about Bain Capital and Romney’s tax returns — that they are likely to create a disturbing, hard-to-watch convention that will fail to offset Romney’s biographic bounce. 

The convention is a show. Americans love to see positive, inspiring, uplifting performances. Negatives turn them off and depress the ratings. Who wants to watch four nights of accusations?

Morris, a former adviser to Sen. Trent Lott (R-Miss.) and President Bill Clinton, is the author of 2010: Take Back America — A Battle Plan and Outrage, Fleeced and Catastrophe. To get all of his and Eileen McGann’s columns for free by email or to order a signed, advanced copy of his latest book Revolt!, go to dickmorris.com.