One of those states is North Carolina, where a Democratic senator is defending her seat in a race the latest polls show could go either way.

　　For most North Carolina voters, this is what next week's Senate election has boiled down to.

　　MAN: Kay Hagan enabled President Obama's worst ideas. She refuses to clean up his mess.

　　NARRATOR: Tillis is a hypocrite, covering up that The Charlotte Observer called on him to resign for missing critical votes.

　　MAN: Senator Kay Hagan says she puts voters first. But she votes with Obama 96 percent of the time.

　　SEN. KAY HAGAN, (D) North Carolina: Speaker Tillis should be ashamed for running an ad that says I would let our soldiers die in vain. That is outrageous.

　　GWEN IFILL: Ninety thousand ads, up to $100 million spent, and clashing messages from incumbent Democrat Kay Hagan…

　　SEN. KAY HAGAN: North Carolina is not for sale.

　　(CHEERING AND APPLAUSE)

　　GWEN IFILL: … and from challenger Thom Tillis, the Republican speaker of the North Carolina House.

　　THOM TILLIS Republican Senate Candidate: We need independent leadership that will stand up to your own party when you disagree with it.

　　SEN. KAY HAGAN: We're going to win. We're going to with your help.

　　GWEN IFILL: The high-stakes political duel has prepared Hagan, who was first elected the year President Obama won North Carolina, and Tillis, who came to power in 2010 after Republicans took over the Statehouse for the first time since Reconstruction, into a genuine final week dead heat.

　　Mac McCorkle teaches at Duke's Stanford School of Public Policy.

　　MAC MCCORKLE, Duke University, Stanford School of Public Policy: Turnout is going to be key for Hagan for her in order to win. There's not going to be a turnout like there was among minority voters and younger voters for Obama in the presidential years. But she's got to get some of that vote.

　　GWEN IFILL: This is not 2008.

　　MAC MCCORKLE: This is not 2008. This is not even 2012. This is a smaller, whiter, older, richer, electorate. It's not an Obama electorate. But she's got to get some of that vote out.

　　GWEN IFILL: At this weekend's state fair in Raleigh, the voters we talked to had already made up their minds. Sara Berth is for Tillis.

　　SARAH BERTH: Well, as in all campaigns, there's always a lot of mudslinging going on, unfortunately, which doesn't interest me. I want to know what the candidate is going to do, what they're not going to do, their beliefs, what they stand on.

　　GWEN IFILL: Andy Jones and his friends are sticking with the Democrat.

　　ANDY JONES: I like Kay Hagan. I like that she has experience. I think that the amount of money that is poured into this race, television ads, is just kind of silly. It's become kind of a very hateful, people just throwing mud at each other and seeing what sticks, and I think that's kind of silly.

　　GWEN IFILL: It's taken a lot of talk and a lot of money for this campaign to go boil down to a simple choice between a Democrat who would rather talk about education and equal pay and a Republican who is anxious to link his opponent to national issues like Ebola and ISIS.

　　The recurring disagreement was on display as we sat down with both candidates this weekend.

　　SEN. KAY HAGAN: Speaker Tillis has put forward the most disastrous legislative record we have seen in North Carolina. He is taking our state backwards. What did he, he gave tax cuts to the wealthy and has balanced the budget on the back of everybody else, the middle class. He's rigged the system against small business, but he has gutted public education.

　　THOM TILLIS: I think if it's about the truth about education, we have the edge there too. We have given a 7 percent raise, the largest raise in about a generation. So if all Senator Hagan has are statewide issues, and nothing to point to at the national level that she's proud of, other than rubber-stamping President Obama 96 percent of the time, I think she's in trouble with the citizens of North Carolina.

　　GWEN IFILL: Tillis mentions Mr. Obama by name in virtually every sentence, never missing the opportunity to link an unpopular president to the state's incumbent Democrat.

　　THOM TILLIS: Senator Hagan knows that President Obama's policies, he said a couple weeks ago, all of them are on the ballot.

　　GWEN IFILL: Does the president hurt your campaign?

　　SEN. KAY HAGAN: You know, this election is about the people of North Carolina. And with the president, I support increasing the minimum wage.

　　I support — I supported his very first bill, my very first bill, the Lilly Ledbetter Fair Pay Act. But I have also opposed the president on things that weren't good for North Carolina.

　　GWEN IFILL: Replacing President Obama on the stump in tight races like this one, Hillary Clinton.

　　HILLARY RODHAM CLINTON, Former U.S. Secretary of State: Elections come down often to who's got more money, who's pedaling more fear, and who turns out. And there is nothing more important for Kay than who turns out.

　　GWEN IFILL: Tillis too has attracted national support, including this visit from GOP Chairman Reince Priebus.

　　REINCE PRIEBUS, Chairman, Republican National Committee: I know that if we work really hard together, that we can get Thom over the finish line, not for the party, not for the majority, for power. We have to do this to help save this country.

　　GWEN IFILL: Both candidates are getting a tremendous boost from outside groups on the right and the left. From the Koch brothers to Planned Parenthood, they have kicked in more of $70 million, two of every three dollars spent on television advertising.

　　CECILE RICHARDS, President, Planned Parenthood: North Carolina very well made determine the future of the United States Senate. And this race between Kay Hagan and Thom Tillis has been a focus for months for us at the Planned Parenthood Action Fund. It is the most important race in the country.

　　GWEN IFILL: To add to the uncertainty, a third candidate, libertarian Sean Haugh, could tip the balance, even if he gets a small percentage of the vote.

　　MAC MCCORKLE: The dynamic is, I don't want to vote for the incumbent, and so I'm looking who I vote for. So, to the extent you vote for a third party, you don't vote for the challenger.

　　GWEN IFILL: Thousands of North Carolinians descended on Lexington for the annual Barbecue Festival this weekend.

　　Thom Tillis supporter Deric Brady was among them.

　　DERIC BRADY: With the federal government, the spending has got so out of control. It needs to be brought down. I'm one that thinks that states, local governments should have more control of the money that they have, instead of sending it to Washington and then having to do stuff to get it back.

　　GWEN IFILL: And William Mciver is one of the thousands of volunteers working the state for Hagan.

　　WILLIAM MCIVER: When we went canvassing, my wife and I, we found that they were like, thank the lord, hallelujah, you showed up. We're here. We're glad to see you. We didn't think you cared about us.

　　GWEN IFILL: But the money, the finger-pointing, the hostile television advertising leaves many voters perplexed.

　　BRYAN DEITZ: It kind of depends on how you view politics. Some people view it as a sport, right? So, it's my team vs. your team. So, whoever has the most money can have a better ground game, because now you need money for television, print, social media, everything else.

　　PATRICIA BALDWIN: There's a lot of money spent, but it's the same thing. It's — one, it's about Medicaid. The other ones are about abortions and birth control and college funds. And it seems like one is for the rich one is for the middle class and the poor.

　　GWEN IFILL: Then there is this last wild card. New voter I.D. laws that Republicans call protection and Democrats call suppression could affect turnout in a state that both national parties now see as their key to the South.

　　JUDY WOODRUFF: And a great report.