SIOUX CITY, Iowa — Republican presidential candidate Mitt Romney claimed Friday that President Barack Obama has failed to fulfill his promises in part because he does not understand what it takes to ignite a more robust economic recovery.
Resuming campaigning after a hiatus during the Democratic National Convention, Romney impugned Obama's competence, not his effort, the day after Obama accepted his party's nomination for president.
"This president tried, but he didn't understand what it takes to make our economy work. I do," Romney told 4,000 supporters at Northwest College in Orange City, the heart of Iowa's GOP-heavy west.
Entering the fall stretch to the Nov. 6 election, Romney is concentrating on Obama's performance, according to aides, to counter what they say are negative depictions of the Republican in Obama campaign ads.
It's also a way to keep the pressure on Obama, without assailing him personally. Although Obama is in a tight battle for re-election, a slight majority of Americans have a favorable opinion of him personally.
In an Associated Press-GfK poll last month, 52 percent of registered voters said they had a favorable opinion of the president, while 46 percent had an unfavorable opinion.
But on the question of who they trusted to do a better job handling the economy, Romney came out on top, 48 percent to Obama's 44 percent. A Washington Post/ABC News poll taken last month showed 56 percent of voters disapproved of Obama's handling of the economy, and 43 percent approved.
That poses a challenge for Romney, who is asking voters to fire a president many of them like. So Romney, who also must change the minds of millions of Obama supporters from 2008 to win, is careful not to insult those voters.
Instead, he characterized Obama as having disappointed supporters who expected more.
Weak job growth in August, as the Labor Department reported Friday, provided more fuel for Romney.
"There's almost nothing the president's done in the last three and a half, four years to give the American people confidence he knows what he's doing when it comes to jobs and the economy," Romney told reporters before the event.
Obama's team, in turn, hopes to use the president's favorable personal rating to make him look caring. They point to a line in the speech former President Bill Clinton delivered at the Democratic convention: "I want to nominate a man who's cool on the outside but who burns for America on the inside."
Obama aides think they can counter the incompetence argument by fleshing out old policy proposals with fresh measurable goals, hoping it shows his sense of determination.
Romney said his campaign achieved one of its goals for the Republican convention in Florida last week, which was to make Romney more personable. Much of the convention amounted to a parade by family members, led by his wife, Ann, as well as personal, church and political associates vouching for his character. It was a strong counter to the image painted of him in Obama ads: A wealthy, uncaring businessman who is out of touch.
In that way, Romney did not hesitate to criticize Obama's campaign, but again stopped short of calling into question Obama's character.
"It's been a campaign of pitting one American against another," Romney said. "And it's so contrary to our national history and our national spirit."
Associated Press writer Jim Kuhnhenn in Portsmouth, N.H., and AP News Survey Specialist Dennis Junius in Washington contributed to this report.