A week of mostly positive press coverage, a star-turn last Saturday night and a tougher, more competitive tone in the debates and on the stump have convinced Sen. Barack Obama, D-Ill., there's a chance now to reshape his political destiny, CBS News correspondent Dean Reynolds reports.
"I disagree with Senator Clinton," he's said on the campaign trail. "Just remember who got it right and who got it wrong in the most important decision! I strongly disagree with Sen. Clinton on her commitment to block a war in Iran."
For Obama, the roll-out is over and the rumble is on.
"It's changed the dynamic in the race," Obama told CBS News. "I think there was a period of time when things were static and people liked what they were hearing from me, but they didn't have a sense that there were significant differences between me and Sen. Clinton."
At stop after stop, Obama tries to draw even sharper distinctions with Clinton on Iraq, on Iran, on immigration and on who could better unite the country.
Voters are taking notice.
"He's sharpening himself and honing himself and I think that's more effective than being Mr. Nice Guy," said Iowa caucus voter Nancy Nieland.
But it's not a risk-free strategy.
"The question is whether Sen. Obama is gonna be comfortable attacking and in fact, the more he attacks, whether that causes some damage to his reputation, in his image and frankly, in his message," said political analyst Stuart Rothenberg.
Obama says playing it safe is for others - Clinton for example.
"I don't fault her for that. That is how people have been taught politics in Washington. That's conventional wisdom, right?" Obama said. "You make yourself a small target by avoiding being definitive about anything."
Democrats have tried that before, he says - and lost.