Mitt Romney has promised to be the agent of change needed to restore US economic health, accusing President Barack Obama of a four-year policy failure that threatens to "crush our future".
With 10 days until Americans vote, the Republican nominee sought to steal Obama's 2008 "change" slogan and brand him a hapless leader, unable to end the slow-growth malaise that has defined the economy.
"The president's campaign falls far short of the magnitude of the times. And the presidency of the last four years has fallen far short of the promises of his last campaign," Romney, 65, told a crowd in Ames, Iowa.
Turning the tables on 2008 Obama, the multi-millionaire private equity baron billed himself as the hope-and-change candidate and the Democratic incumbent as representing the political "status quo".
"President Obama promised to bring us together, but at every turn, he has sought to divide and demonise. He promised to cut the deficit in half, but he doubled it," Romney said.