AMANPOUR: So you're glad that it's O'Donnell who won the primary?
COONS: I'm not sure it's good for Delaware or good for Delaware's voters.
AMANPOUR: Do you, for your campaign?
COONS: Obviously, I went from being significantly down to significantly up in the polls, so just from an outside-in view, it's a positive in terms of my chances in the election. But I don't think it's been positive for Delaware. There's been a huge amount of attention paid to things that aren't directly connected to what matters to Delaware.
AMANPOUR (voice-over): And Tom Ross, chairman of the state Republican Party, was clearly agitated when he joined me on "This Week" just days after O'Donnell won the primary.
(on-screen): You are not a happy man today.
ROSS: I'm not a happy man. We have worked very diligently in a very difficult environment. I'm the Republican chairman in the Northeast. My state is vastly Democratic. Most people identify themselves as a moderate. We had a candidate that was very close to becoming the next United States senator from Delaware, and essentially people on our own team clipped him right as he was about to go on the goal line.
AMANPOUR (voice-over): Ross told me O'Donnell's support comes from Tea Party backers across the country.
ROSS: You know, we're not opposed to Tea Party values. What we're opposed to is people coming in from out of state and dumping hundreds of thousands of dollars on candidates that we have not endorsed.
AMANPOUR: O'Donnell may be trailing Coons in the polls, but she's raised three times more money than he has, $3.8 million in just over a month.
BIDEN: We want to make sure Chris has the money to continue -- to finish out this campaign.
AMANPOUR: And as the vice president told "Nightline's" Terry Moran, that got their attention.
BIDEN: Look, Christine ran against me. I'm the only guy in America that at the same time ran -- had two opponents, Christine O'Donnell and Sarah Palin, because I was on the ticket in Delaware as a senator and as vice president. And I took them both very seriously. We take Christine O'Donnell seriously.
One of the reasons is, Christine O'Donnell has been able to raise a great deal of money. There's an awful lot of negative ads she's been able to put up.
O'DONNELL: We haven't yet taken out a negative ad.
AMANPOUR: Expect, perhaps, this one...
(UNKNOWN): You will hide your lights, because he's taxing everything out here. Chris Coons is the Taxman.
AMANPOUR: If he's elected, Chris Coons told me tax policy will be a top priority.
COONS: I would vote to extend the overwhelming majority of the Bush tax cuts. There's a trillion dollars in private capital sitting on the sidelines right now in the American economy. All that money is sitting there waiting for clear signals about health care costs, about where we're going in tax policy, and what we're going to do to restart this economy. We have to get these things solved.
O'DONNELL: There's this scare tactic coming from the Democrats saying that these tax cuts for the rich are these billionaires who are trying to find places to dock their yachts. That's not it at all. It's the dry cleaner down the street. It's the pizza shop owner down the street. It's the hardware store owner.
COONS: She's run for the -- for the United States Senate three times in five years. That's a lot of persistence.