JUDY WOODRUFF: And we come back to the campaign and an increasingly polarized environment.
The passion from supporters of both parties leading up to yesterday's vote in Wisconsin is just one slice of a national trend, and one that is growing, according to a new poll. The Pew Research Center's American Values survey has tracked Americans' attitudes on a variety of issues over the past 25 years.
Asking about views on government, business, the environment and social issues, Pew researchers found this year that partisan divisions have grown more intense than ever.
Andrew Kohut is the Pew Center president.
ANDREW KOHUT, Pew Research Center: When we first started doing this in 1987, we found that income, education, race, and party affiliation were all about equally important or influential in shaping political -- views about values. Now, however, we find that education, income and the range of demographic factors continue to be as influential as they were in 1987, but the influence of party affiliation has doubled.
JUDY WOODRUFF: When Pew began asking its set of value-oriented questions in 1987, the average disparity by party was 10 percent. By 2012, the partisan gap had nearly doubled to 18 points.
ANDREW KOHUT: Almost all of the increase that we see occurred not gradually over the past 25 years, but in the past 10 years, that is to say during the administrations of George W. Bush and now Barack Obama.
By the middle of his first term, most Democrats strongly disapproved of George W. Bush. And almost from the get-go, most Republicans have strongly disapproved of Barack Obama. So part of it Is response to these presidencies and the political culture. Part of it, too, is the way the parties have changed. The parties have become smaller than they once were. We have a record number of political independents.
JUDY WOODRUFF: In fact, an unprecedented 38 percent of those surveyed identified as independents, the most to choose that description at any point in the last 75 years.
By comparison, just 32 percent said they were Democrats, and only 24 percent now call themselves Republicans. Throughout this election year, the NewsHour wants to hear from all these categories of voters from across the country as a part of our "Listen to Me" project. And while we're just getting started, by November 6, we will collect a rich tapestry of voices, including many independents.
GREGORY NELSON, Texas Independent: I think there's too much division. I think that they don't have a common goal. They don't want to partner together. They want to blame the other side, blame the past. There's too much, well, what Bush did. There's too much of what Reagan did, what Clinton did. And they won't even come together. They're there right now.
The Obama administration and the Congress, the Republicans and Democrats, need to work together.
JUDY WOODRUFF: So what does this polarization mean for the 2012 presidential election? Pew found the most notable divisions are in areas where President Obama and his Republican challenger, Mitt Romney, appear to differ the most.
ANDREW KOHUT: If you look at one set of values that differentiates Republicans from Democrats, it's about the role of government, not only in general, but with respect to a whole range of things, from continuing to provide entitlements to concerns about the growing power of government. And those questions will be, I think, central to the choices of many, many, many voters.
JUDY WOODRUFF: One major sticking point, health care. When asked about the government's role in health care, 88 percent of Republicans say the government is too involved; 61 percent of independents agree, but only 37 percent of Democrats.
And many of our "Listen to Me" voices reflect that divide.
LAUREN PAGNARD, Colorado Republican: The most important issue for me is repealing Obamacare, because I believe that it goes against our constitutional rights and is going to financially bankrupt the country.
JACK CRAWFORD, Indiana Democrat: Health care's an example. I support the health care plan as passed by the Congress and supported by the president. We have got to do something.
JUDY WOODRUFF: You will be hearing more voters like these in the coming weeks on the "Listen to Me" page on our website, NewsHour.PBS.org.
So, what does it mean that more Americans are turning away from the political parties?
To explore this, we turn to Linda Killian. She's a senior scholar at the Woodrow Wilson Center and she's the author of the new book "The Swing Vote: The Untapped Power of Independents."
Linda Killian, thank you for being with us.
LINDA KILLIAN, Woodrow Wilson Center: Thanks for having me, Judy.
JUDY WOODRUFF: So, first of all, who are these inspects? We just heard Andy Kohut say they are now 38 percent of the electorate. Tell us who they are in terms of age, gender, income level.
LINDA KILLIAN: Well, they're very diverse.
Since it's a larger group than either Democrats or Republicans, you can imagine that they are very diverse. They're all over the country. Obviously, they matter more when they're in swing states, battleground states.
I talked about four, Colorado, Ohio, New Hampshire and Virginia, which will be at the key of this election. And in interviewing hundreds of swing voters, independent voters around the country, I identified four key constituencies, NPR Republicans. These are what we used to call Rockefeller Republicans, socially liberal, fiscally conservative.
America-first Democrats, we used to call those Reagan Democrats. These would be voters like those in Wisconsin -- 18 percent of the voters who voted for Scott Walker said they intend to vote for Barack Obama, big chunk of these conservative Democratic voters.
Young voters, I call them the Facebook generation. They're registered as independents in a higher percentage than any other age group. And the power group are suburban voters, Starbucks moms and dads. They swing elections, suburban and exurban voters. The election will be decided in suburbs.
JUDY WOODRUFF: And just to clarify, who is in these groups classifying themselves as independent shifts from election to election. That's what we heard in that Wisconsin piece.
LINDA KILLIAN: It does. They change their minds. They swing.
JUDY WOODRUFF: And what's your understanding for why the numbers of these folks have grown?
LINDA KILLIAN: They are very disaffected with the two parties. They're very dissatisfied. It's like they're vegetarians, and the Democrats and Republicans are offering steak and chicken.
They're very unhappy. They don't like the negativity. They want substance. You heard your first voter there talking about, they want more substance. They hate money in politics. They are concerned about the deficit. Obviously, jobs and the economy are their top two issues. For independent voters, they care very much about substance, the deficit.
JUDY WOODRUFF: And in terms of what they believe in, do they have like a mix of views or is it just that they don't feel as strongly as do the hyper-partisans on both sides?
LINDA KILLIAN: Well, I think a myth about independent voters is that they don't care and they're not informed and they're just wishy-washy.
That's not true. The independent voters I talk to care very deeply about this country. It's just that they do have a mix of views and they don't feel comfortable in either party. They're socially tolerant. They feel like that things like abortion, gay marriage, birth control, the government doesn't have a role in these.
And so they care less about those issues. A majority of them agreed with what Barack Obama did on gay marriage, but they say it won't affect their vote because they just don't care that much about it. But they are very concerned about issues like the economy, like the deficit and being more fiscally responsible, having government that makes sense.
JUDY WOODRUFF: And picking up on some of those definitions, those descriptions that you used a minute ago, how truly independent are they? How much -- because we -- I noticed the Pew survey said most of them lean toward one party or another. So what does that mean?
LINDA KILLIAN: This is another thing. It makes them mad. I'm telling you, interviewing independent voters, this -- this thing saying that they're not independent really angers them.
Yes, a number of them lean Democrat and Republican and consistently vote -- they have become independents for a variety of reasons. But Pew surveys, a variety of exit polls, I think it's very fair to say half of all the independent voters -- so that would be about 20 percent of all registered voters, if 38 percent are independents -- are truly swing independent voters.
And you can see that from 2008 to 2010 and what happened with the way independent voters voted.
JUDY WOODRUFF: And, finally, what does all this mean for President Obama in the fall and Gov. Romney?
LINDA KILLIAN: Well, it means they're going to have to work hard is what it means.
It means that these swing voters are up for grabs. They haven't made up their minds. I don't think they will make up their minds until October. And they're going to watch the conventions. They're going to watch the debates. And they will vote, I think, for the most part based on who they think is going to be best for the economy and jobs.
JUDY WOODRUFF: And what does that say about the message, the way that either Romney or President Obama tailor their message?
LINDA KILLIAN: They should be substantive. They should talk about what they're going to do.
We have all these fiscal cliffs hanging at the end of the year, taxes expiring, triggers on the -- on spending. They should talk about substance and what they would do for the country and to solve the country's problems.
JUDY WOODRUFF: Linda Killian, author of this new book on the swing vote, "The Untapped Power of Independents," thank you very much.
LINDA KILLIAN: Thank you for having me.
JUDY WOODRUFF: And a reminder: You can watch those "Listen to Me" videos on our Politics page.