The 2000 election supports arguments both for and against the "who will win" question's ability to predict presidential results. A CBS News poll found that 47 percent of Americans expected Bush to win, compared to 33 percent for Al Gore. Gore won the popular vote that fall, but Bush won the Electoral College vote, and thus the White House.
In August polls in 1992 and 1996, Americans correctly predicted Bill Clinton's wins over incumbent George H.W. Bush and challenger Bob Dole, respectively. In August 1988, a poll similarly found confidence in Bush's eventual win over Michael Dukakis.
"Any indicator that has been as reliable as this, for whatever reason, has to be taken seriously," Kohut said.
It's impossible to read voters' minds. But the combination of low faith in Romney's ability to defeat Obama and his relatively low favorability ratings suggests he has yet to persuade most Americans he is cut from presidential timber.
There's ample time to remedy that. And, of course, the weak economy might sink Obama without Romney having to raise his popularity.
Romney's camp undoubtedly wants to use the convention's remaining hours — especially his Thursday night acceptance speech — to burnish his likability and plausibility. There's work to do.
Most registered voters viewed Romney unfavorably when the convention opened, a recent Washington Post poll found. He is the first party nominee with higher unfavorable than favorable ratings at this stage since Walter Mondale, the 1984 Democratic choice.
In the same poll, 61 percent said Obama was more "friendly" and "likable" than Romney; 27 percent saw it the other way around.
Several Republican strategists said they are not terribly worried about Americans' predictions of the Nov. 6 winner.
"That data fails to measure the intensity that voters bring to the table," which favors Republicans, said veteran consultant Terry Holt. "Romney still has to close the sale, but he's still got plenty of time."
Holt added: "I'd be more concerned if it were two or three days before the election."
Millions of Americans will tune in Thursday night for Romney's acceptance speech. Aside from the three October debates with Obama, it will probably mark his best chance to start closing the plausibility gap.
EDITOR'S NOTE — Charles Babington covers national politics for The Associated Press. AP deputy polling director Jennifer Agiesta contributed to this report.
- Over 100 missing, 14 dead as strong quake...
- Rubio faces barrage of attacks in Republican...
- 5 things to know about the Super Bowl and sex...
- Search for possible survivors of midair crash...
- N. Korea praises launch, others see as covert...
- Pope's sex abuse panel tells survivor to take...
- Police think 6 Chicago deaths result of...
- Charity parodies -- videos tell another side...
- US adds just 151k jobs in January; 4.9... 29
- Donald Trump calls for Iowa election... 14
- Kentucky Sen. Rand Paul quits 2016 GOP... 12
- Once a bromance, now a brawl: Trump and... 10
- 5 things to know about the Super Bowl... 9
- In a U.S. divided on gun control,... 8
- Did the media gloat over Trump's Iowa... 8
- It's official: Clinton wins Iowa,... 6