President Obama and Mitt Romney are waging one of the most partisan campaigns in recent memory, energizing their bases with heated rhetoric and harsh tactics. But among political independents, some of the most prized voters in the electorate, speaking more softly about the other side may be a key to winning their support.

Independents make up about a third of all voters. They constitute about half of those who are uncommitted in their choice for president. And they are one of the most mischaracterized groups in the electorate.

Independent voters are not a monolithic bloc. Nor are many of them truly independent in their voting patterns, according to a new study by The Washington Post and the Kaiser Family Foundation. Nearly two-thirds of Americans who describe themselves as independents act very much like partisan Republicans or partisan Democrats.

Still, one clear factor that separates them from Democrats and Republicans is a near-uniform call for greater cross-party cooperation. Seven in 10 independents say they favor compromise between the parties rather than confrontation, according to the survey. Just as many say they are dissatisfied with the country’s political system.

Much of the time, the Obama and Romney campaigns seem tone-deaf to that sentiment; the harshness and negativity of the race seem designed to mobilize partisans on both sides. At other times, the candidates seem keenly attuned to some voters who want leaders willing to cooperate with their opponents.

Obama regularly talks about his desire to find bipartisan consensus, even if he has not delivered on his 2008 pledge to change politics in Washington. Romney, his Republican challenger, said in introducing Rep. Paul Ryan as his running mate that the Wisconsin congressman has regularly tried to work with Democrats, even though Ryan is perhaps best known as the author of a GOP budget plan sharply criticized by Democrats.

The Post-Kaiser findings are based on a national survey of more than 3,000 randomly selected adults, designed to provide a fresh, in-depth examination of the Democratic and Republican parties, the widening gulf between them, and their important internal divisions. In parallel, we use the data to explore the views of the growing number of people who decline to pledge allegiance to either party.

Independents are often described as the holy grail of American politics. They are the heavily courted voters commonly thought to hover somewhere in the center of the ideological spectrum and whose attitudinal swings can make the difference between celebration and dejection on election night.

As a group, independents have been a volatile segment in recent elections: going for Republican House candidates in 2010 by a record 19-percentage-point margin, after breaking for Democrats by 18 points when they won the House of Representatives in 2006. In the five congressional elections before that, neither party had a clear edge among these voters. Obama won independents by eight percentage points in 2008, according to the network exit poll.

This November, independents again could play a decisive role. They make up 49 percent of those who are undecided or say they could change their minds.

In some states, the numbers of independents or nonaffiliated voters are growing faster than are Democrats or Republicans. In many polls, those who call themselves independents outnumber Republicans or Democrats.

But many are neither centrist nor moderate. And many don’t really swing back and forth from one party to the next with any regularity. About a third are indistinguishable from Democrats, and three in 10 are indistinguishable from Republicans, at least when it comes to their voting patterns.

Those who are both genuinely independent and active participants in the political process constitute only a sliver of the overall electorate — about 5 percent, according to the new survey. And among that group, just one in three say they are firmly settled in their choice between Obama and Romney.

Still, even this small share of votes could prove decisive in a campaign that has been tightly fought in its initial months. But given the fact that such voters are few in number, the two campaigns are spending more time mobilizing party loyalists than on persuading the undecided. Some of those loyalists, however, call themselves independents.

Four kinds of independents

The Post-Kaiser survey identifies four distinct groups of people who identify as political independents. About a third of all independents share the bulk of their political opinions with Democrats, regularly vote Democratic and overwhelmingly back Obama’s reelection bid. A similarly large share sides with the GOP on most issues, sharing similar values, attitudes about government and voting patterns. Most support Romney.

About one in four adults who call themselves independents are more or less detached from the political process. Most are not registered to vote, with few saying they plan to enroll before Election Day. These tend to be younger and heavily Hispanic, and have much less education and far lower incomes than others who describe themselves as independents.

That leaves about one in eight who are “deliberators” — quintessential swing voters. Most say they’ve always considered themselves to be independent, and fully half say they’ve voted for Democrats and Republicans about equally in presidential elections. In fact, as a group they divided almost down the middle in 2008 between Obama and the Republican nominee, Sen. John McCain (Ariz.).

Look at almost any poll — including Post and Kaiser Family Foundation surveys — and the views of independents typically fall close to the results for the overall population. That reinforces the importance of understanding where independents sit, but it also conveys an impression that they are all middle-of-the-road voters. What this misses is that on many issues, large numbers of independents have attitudes that are largely indistinguishable from one side or the other.

Overwhelming majorities of “disguised Republicans” say they trust the GOP over the Democrats on the economy, health care, the budget, taxes, social issues and foreign policy. Most of these independents would prefer abortion to be illegal in all or most circumstances, and they oppose same-sex marriage. They say the policies of the Democratic Party hurt their families’ economic interests. About eight in 10 say they plan to vote for Romney in November, with most saying they “definitely” back him.

“I agree with about 80 percent of the Republicans, and about 80 percent I disagree with the Democrats,” said Hugh Fleet, an independent who plans to support Romney despite seeing him as too liberal. “Neither party is 100 percent pro-family, it’s just the Republican Party is more so.”

At the other end of the spectrum, more than eight in 10 “disguised Democrats” say they plan to vote for Obama. Like self-identified Democrats, they favor a path to legal status for illegal immigrants, give Obama’s health-care plan a strong show of support, want to see gun laws strengthened and say they would prefer to see more spending by Washington to create jobs rather than worrying about increasing the federal budget deficit. And they say Republican policies hurt their economic interests.

‘Sick of them’

For some Americans, the term “independent” is merely confirmation that they’ve tuned out of the political process. Among this bloc of “detached” independents, seven in 10 are not registered to vote, and nearly nine in 10 say they did not vote in 2008. Just 16 percent say they are “very interested” in this year’s contest.

“Washington is just a bunch of liars and thieves, and I’m just kind of sick of them,” said Scott O., who would not provide his last name for publication. He said he did not vote in 2008 and has no plans to register this year.

More of these independents favor Obama than Romney, but they lean toward the Republicans on the biggest issue of the day: On the economy, detached independents side with the GOP over the Democrats by a 17-point margin. At the same time, they lean progressive on abortion and same-sex marriage.

The classic independents — whom we call “deliberators” — are not uniformly middle-of-the-road in their views on issues. But they share a deep dislike for the way the political system is operating: Fully 91 percent are dissatisfied with the political system, and 75 percent trust neither Democrats nor Republicans when it comes to representing their opinions on the economy.

They overwhelmingly say GOP and Democratic leaders are taking their parties in the wrong direction, and most see each party’s policies as hurting their families’ economic interests.

When politicians and commentators talk about Americans who hate Washington, these true independents embody that view.

“I don’t know what the truth is or what the lies are,” said Voula Manukas of Raleigh, N.C. “If I had my choice, I’d vote them all out and put a new Congress in there that’s going to work and not spend their whole time on the rhetoric.”

Overall, nearly half of them say they are moderate politically, and about a third say so about their views on social issues. On fiscal matters, almost half of them describe themselves as conservative, while close to four in 10 say they are moderate. The rest, just one in 10, call themselves fiscal liberals.

The economic leanings of these independents make them appealing targets for the Romney campaign. A majority say they prefer holding the line on spending to avoid making the deficit larger, rather than spending more to create jobs. But on social issues, from abortion to same-sex marriage, their views are more in line with Obama’s positions.

Economic issues are dominant in the campaign, but Obama’s team has been running ads aimed at appealing to women based on Romney’s positions on social issues. Those ads appear designed to mobilize Democratic-leaning female voters and attract the support of independent women who favor abortion rights or same-sex marriage.

Deliberators favor smaller government and think that government controls too much of our daily lives. And nearly six in 10 say they prefer to keep the Medicare program the way it is, rather than move to a plan favored by Romney and Ryan in which the government would give people money to help them purchase health insurance — an opinion shared by most disguised Democrats.

Putting all four groups together, a slim majority of independents oppose such a shift in the Medicare program, but most also give a higher priority to deficit reduction than new spending, and more than six in 10 would prefer a smaller federal government. These broad views set the challenges for Obama and Romney when it comes to appealing to anyone other than overt partisans.