Barack Obama offered his closing argument in the race for the White House as he returned to his message of hope for America and linked Republican rival John McCain to increasingly unpopular President George Bush.
With just eight days to go until election day, Mr Obama is looking to consolidate his lead in national polls as he lays out the choice facing the nation.
But Mr McCain faces internal party disputes as he tries to paint his Democratic rival and a Democrat-controlled US Congress as "dangerous" for America.
Speaking in Canton, in the key battleground state of Ohio, Mr Obama said: "In one week, you can put an end to the politics that would divide a nation just to win an election; that tries to pit region against region, city against town, Republican against Democrat; that asks us to fear at a time when we need hope.
"In one week, at this defining moment in history, you can give this country the change it needs."
The 47-year-old Illinois senator went on: "After twenty-one months and three debates, Senator McCain still has not been able to tell the American people a single major thing he'd do differently from George Bush when it comes to the economy.
"Senator McCain says that we can't spend the next four years waiting for our luck to change, but you understand that the biggest gamble we can take is to embrace the same old Bush-McCain policies that have failed us for the last eight years. We can't afford to take that risk."
Mr Obama said his rival did not represent change for America and added: "That's why he's spending these last weeks calling me every name in the book. Because that's how you play the game in Washington. If you can't beat your opponent's ideas you distort those ideas and maybe make some up. If you don't have a record to run on, then you paint your opponent as someone people should run away from.
"You make a big election about small things. Ohio, we're here to say, 'Not this time; not this year; not when so much is at stake.'."
