For a generation, he has been considered a model of conservatism in Washington – at moments, perhaps, the model. Over the course of his 34-year career, US Sen. Orrin Hatch (R) of Utah has clashed with Big Labor. He has championed right-wing judicial nominees. He has consistently opposed federal gun control measures and backed a constitutional amendment to ban same-sex marriage. He has sponsored or cosponsored a balanced budget amendment – which would require Congress to spend no more than it collects in revenues – no fewer than 17 times. In 2010, the American Conservative Union gave him a perfect 100 ranking.

Yet today Mr. Hatch faces formidable opposition – for not being conservative enough. Activists on the right are attacking him for his vote for the Troubled Asset Relief Program, the financial-market bailout initiative, and his willingness to work with Democrats like the late Sen. Ted Kennedy. They complain that he has voted to raise the debt ceiling 16 times. It's looking increasingly as if Hatch will face a Republican primary challenger next year – and could very well lose.

In some respects, this is simply a case of a senator who's spent more than three decades in Washington butting up against a public mood that is intensely antiestablishment and – particularly on the right – opposed to compromise. Like most longtime public servants, Hatch has cast a number of difficult votes over the years, and he has at times reached across the aisle in order to get things done.

But Hatch's troubles also say something about the way in which the nation's political needle has been moving. Over the past four decades – and more sharply over just the past few years – the geopolitical center of America has shifted rightward. It hasn't happened on all fronts – certainly, there are some areas where the country has clearly moved to the left, such as views on gay rights. But on a host of other issues, from guns to the role of government, the center of debate has edged closer to the conservative position, while activists on the right have moved even further out on the political spectrum.

The move has been most pronounced on fiscal matters. In Washington today, when it comes to the size of government, the debate isn't over whether to cut spending, but by how much. It's not over how much to raise taxes to help alleviate a fiscal shortfall, but whether any kind of tax increase – even on the wealthiest few – is valid.

"I don't remember, ever, in my 45 years in this business, the debate in Washington being [almost solely], 'What are we going to cut?' " says Sal Russo, a top strategist for the Tea Party Express and a longtime Republican consultant who worked as an aide to Gov. Ronald Reagan and advised Hatch's 2000 presidential bid. "Washington is different than anything I've seen in 45 years."

When it comes to foreign affairs, a country that went into a crouch for two decades after Vietnam is now involved – however reluctantly under the current president – in three wars. Many Americans have also hardened their stance on illegal immigration, accountability in schools has become a prevailing ethic, and nuclear power and offshore oil drilling have come back, to a limited degree.

Compared with today's Republican presidential candidates, Barry Goldwater, the founder of the modern conservative movement – whose views were considered so extreme in 1964 that he was defeated in a landslide – would seem almost temperate. His blend of strict constitutionalism, muscular national security, and small-government economic policy – low taxation and light regulation – has become standard boilerplate on the stump today. And his more moderate social stances – he believed the government shouldn't interfere with a woman's right to choose to have an abortion, for instance – would set him to the left of many. This is one reason he told Bob Dole in 1996: "We're the new liberals of the Republican Party. Can you imagine that?"

In that sense, it may not be Hatch who has changed but the voters he's trying to cater to – and the definition of what it means these days to be liberal or conservative.

"Everybody talks about the fact that Nixon and Ford were the last liberal presidents – and to a great degree, it's true," says Larry Sabato, a political scientist at the University of Virginia. Or as liberal comedian Bill Maher put it in an interview with CNN, "Really, what we have is a debate between the center-right – the Democratic Party – and the far, far, far right – the Republican Party."

Beneath all this lie fundamental questions: How much has the country really tilted to the right? What's behind the shift? Is this the last gasp of a realignment that has been going since the 1970s, or are we seeing the emergence of a new brand of conservatism that may persist for years?

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Actually, when asked to describe their ideological leanings, the basic pattern of responses from voters hasn't changed dramatically in 40 years. Self-identified conservatives have always outnumbered self-identified liberals, and for the most part, both groups have tended to trail behind self-identified moderates.

Still, over time – and particularly in recent years – there has been a small but significant shift in favor of conservatism. When CBS News asked voters to categorize themselves in February 1976, 28 percent called themselves conservative, 23 percent called themselves liberal, and 39 percent called themselves moderate. By June 2010, those numbers had shifted to 35 percent conservative, 18 percent liberal, and 42 percent moderate.

In some recent polls, conservatives have actually begun to outpace moderates. According to Gallup, 40 percent of Americans identified themselves as conservative in 2010, compared with 35 percent as moderate and 21 percent as liberal.

Perhaps most striking, last February Gallup released state-by-state results that showed self-identified conservatives outnumbering self-identified liberals in every state in the nation – including Vermont, Massachusetts, and New York.

Of course, these are subjective labels – they almost certainly mean different things to different voters in different places and at different times. But if anything, as more and more voters are calling themselves conservative, the definition of what that means – and the implications it holds for policy – also seems to be shifting right.

In 1976, when Hatch was first elected to the Senate, the government had been steadily expanding for four decades, beginning with Franklin Roosevelt's New Deal, and continuing with the enactment of Lyndon Johnson's Great Society – launching Medicare and Medicaid as well as other social programs. Some of them were further expanded under Presidents Nixon and Ford. By the mid-1970s, concern was growing that things were getting out of hand: In a Gallup poll that year, when asked to rank "government spending" as a concern on a scale of 1 (least important) to 5 (most important), 57 percent gave it a 5.

The nation was also struggling with the end of the Vietnam War and the Watergate scandal, as well as battling double-digit inflation, high interest rates, and an unemployment rate of 7.7 percent.

"The people and the voters … are skeptical and sour," wrote Michael Barone in the 1976 edition of the "Almanac of American Politics." "They doubt government can accomplish much, and they don't believe in politicians."

The national malaise gave momentum to a rising breed of conservative politicians like Hatch – who, at the time, was a young Salt Lake City attorney with no political experience. Hatch argued that reducing the size of government, rolling back regulations, and lowering taxes, along with a renewed focus on morality and building up the military, would reenergize the nation.

That same year, Mr. Reagan challenged President Gerald Ford in what wound up being a surprisingly close Republican primary contest. (Reagan also played a critical role in Hatch's senatorial campaign, endorsing him as a fellow conservative.) Four years later, Reagan would oust Jimmy Carter from the Oval Office, launching a conservative wave that – despite some electoral ups and downs – has shaped the national debate to a considerable extent ever since.

Today, some of the same forces that launched the modern conservative movement are coming into play once again – from concerns about federal spending, to distrust of government, to fears about America's decline in the world. But there are some notable differences, too, that have shifted the nation's political center on certain issues even further to the right.

Instead of coming on the heels of a great liberal expansion of government, today's shift comes after three decades of the unraveling of elements of the social safety net. The move right is starting from a more conservative standpoint. Taxes were dramatically lowered by Reagan, and have remained relatively low ever since (today's top marginal tax rate is 35 percent; in 1976 it was 70 percent). A Democratic president – Bill Clinton – ended "welfare as we know it," and enacted business-friendly trade policies that quickened the flow of manufacturing jobs overseas. Organized labor has dramatically declined in power.

"The New Deal programs have been weakened and destroyed over decades, and there are just many fewer elements in the safety net," says Alan Brinkley, a historian at Columbia University and author of "Liberalism and its Discontents."

Conservatives, of course, would argue that any tilt to the right is a validation of their ideas. Yet the situation is more complex than that. Many factors have contributed to the nation's rightward drift.

For one thing, frustration over what is perceived as wasteful government spending – under both Democratic and Republican administrations – has grown. The Bush administration's massive spending on everything from a new prescription drug bill to the war in Iraq pushed the national debt to new heights, a trend that has continued during President Obama's tenure. Voters saw the government spend huge sums on such things as financial bailouts and health care – little of which seemed to make a noticeable difference in people's lives.

For many voters, it's a sense of, "we've spent all this money, and there's still 9.2 percent unemployment," says Democratic pollster Anna Greenberg. "There's this larger question: Can government actually do anything?"

Voters still strongly support Social Security and Medicare, and do not want to see those programs dismantled. When Fox News asked voters last May to choose between making cuts in defense or Social Security and Medicare to balance the budget, respondents chose defense, by 54 percent to 22 percent. But between the rising costs of entitlements and an aging population, the nation's finances have grown increasingly dire – and voters place blame on both parties.

Indeed, one of the main forces behind the recent rise in conservative views – particularly on the issue of the size and role of government – is a widespread sense that the political system is fundamentally broken: Politicians on both sides of the aisle are seen as big spenders who are tools of special interests.

As a result, while the nation may be moving right in its attitudes about what government can and should do, it has also been moving away from traditional party loyalties. Many people are identifying themselves as conservatives first and Republicans (and to a lesser extent Democrats) second.

"One of the reasons you're seeing a more conservative attitude among conservatives is a belief that Washington and both parties have ignored their concerns," says Republican pollster Glen Bolger. "The spending continues to go up, the debt continues to go up. I think they're saying, 'Look, we're kind of getting tired of people saying, "Yeah, we hear you," and then doing nothing.' "

This sourness about government has led conservative activists to hold even Republican officials to more stringent tests – requiring them, for instance, to sign "no new tax" pledges. And increasingly, they are willing to challenge those politicians who fall short, pushing them further to the right.

In Hatch's case, he has been making notable efforts to shore up his conservative credentials. In recent months, he has renewed his push for a balanced budget amendment and introduced a measure that would prevent minors from traveling across state lines to get an abortion without parental consent. During the debate over the debt ceiling, he made a speech on the floor of the Senate arguing that the rich are shouldering an outsized portion of the tax burden: "The poor need jobs, and they also need to share some of the responsibility."

He has reversed his stance on a bill that would allow young illegal immigrants who grew up in the United States to pursue citizenship – a measure he had previously cosponsored with Mr. Kennedy – and he has said publicly that his vote for the financial bailout was a mistake.

"It might be true that Hatch did moderate a little bit – partly because he was in a position of responsibility and leadership that required that he be willing to talk to the other side. But he's certainly dialed that back in recent months," says Quin Monson, a political scientist at Brigham Young University. "In some ways, it's disappointing and sad that reaching across the aisle has become anathema to Republicans. It makes you wonder where it ends."

Mr. Russo, whose group, the Tea Party Express, has said it will not challenge Hatch, calls him a "stalwart conservative." "I think there's a 'slash and burn' mentality," he says about efforts on the right to unseat Hatch. "Some people have unreasonable views about how you get things done."

Yet it isn't just Republicans who are becoming more conservative about Washington's role. In its most recent biannual survey of political values and core attitudes, the Pew Research Center found that the most notable shift of late is that independent voters have taken "a turn to the right" on broader economic issues, including views of the social safety net and the government's effectiveness and scope. Pew found that the number of people who believe the government "should help more needy people even if it means going deeper into debt" has fallen to 48 percent overall, while among independents, it's down to 43 percent – a drop of 14 points since 2007.

"There's more concern about the debt, and distrust of government – and an unwillingness to use government to do things," says Andy Kohut, Pew's director. "We don't like the way we're bailing out banks, but we also don't like the way we're bailing out people who've taken out mortgages and can't afford them."

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Tough economic conditions may be another reason many people's attitudes are hardening about government. Studies, including one in 2010 by Peter Enns of Cornell University and Nathan Kelly of the University of Tennessee, found that when income inequality widens, both rich and poor Americans tend to grow more fiscally conservative.

During the liberal heyday of the 1930s and '40s, income inequality actually narrowed, and then remained relatively stable throughout the '50s and '60s. It wasn't until the '70s that it began widening, launching what liberal economist Paul Krugman has famously called "the Great Divergence." In 1976, the richest 1 percent of Americans took home 9 percent of the nation's total income; today, they are taking home 24 percent.

Mr. Enns and Mr. Kelly don't know exactly why lower-income voters tend to grow more fiscally conservative in response to inequality, but they speculate that one factor may be the media. The widening gap since the 1970s has been largely due to massive gains among the wealthy – and media narratives during this time probably emphasized stories of bootstrap "individualism."

In contrast, the decrease in inequality during the decades prior to the '70s was driven by income gains among the poor and may have generated news stories emphasizing the government's role in education and job creation. "This could explain why declining inequality up to the 1970s pushed public opinion in a liberal direction," they write – and why rising inequality in recent decades has shifted voters further to the right.

On other issues, jarring events have helped move the country to the right. The nation's foreign policy has been more hawkish in the wake of 9/11, and even Mr. Obama, who came into office vowing to end the wars in Iraq and Afghanistan, has found it difficult to do so on an aggressive timetable. The Guantánamo Bay detention facility remains open, and homeland security is still a widespread concern.

"Foreign policy doesn't change that much from one administration to another," notes Professor Brinkley. "It's hard to persuade either the electorate or the government that we're not going to be the protectors of the world anymore."

Of course, there are counterpressures pushing America in a more liberal direction, too. Generational changes are clearly pushing public opinion to the left when it comes to certain moral and cultural issues, most notably gay rights.

When Gallup asked voters in 1976 whether homosexuals should have equal rights in terms of job opportunities, 56 percent said they should, while 33 percent said they should not. But when asked if homosexuals should be allowed to teach in elementary schools, 65 percent said they should not, while only 27 percent said they should. Only 14 percent of voters believed homosexuals should be allowed to adopt children, while 77 percent said they should not.

Today, by contrast, a majority of Americans support same-sex marriage – 53 percent, according to the latest Gallup poll, compared with 45 percent opposed. And 67 percent told Gallup they'd support a law allowing gays to serve openly in the US military.

Yet the direction of the country on other social-cultural issues remains less discernible. Many states have imposed more restrictions on abortion, for instance, suggesting a tilt to the right. But Roe v. Wade remains intact, and many polls show a majority of Americans support a woman's right to terminate a pregnancy if it's in the first few months.

Likewise, on gun control, polls suggest a rightward shift in views over the past decade – the Harris Poll found the proportion of Americans who favor stricter gun laws fell from 69 percent in 1998 to 45 percent in 2010. But that 45 percent still represents a plurality, compared with just 26 percent of Americans who want less strict gun laws.

Global warming, which wasn't even an issue in the 1970s, has become a broad concern today, although Americans seem to have become more skeptical of late: Harris found that the percentage of Americans who say they believe that an increase in carbon dioxide and other gases will lead to global warming fell from 71 percent in 2007 to 51 percent in 2009. And views on the death penalty have also moved leftward, no doubt in response to questions about wrongful convictions sparked by the rise of DNA evidence. Although most Americans still support the death penalty, Gallup found that support dropped from a high of 80 percent in 1994 to 64 percent in 2010.

To many observers, one factor that will shape the nation's views on many of these issues in the future will be demographic changes, including the rise of the Hispanic population. By the year 2050, nearly 1 in 5 Americans will be foreign-born – a percentage that outpaces the previous peak reached at the beginning of the last century, when waves of European immigrants hit America's shores. Analysts say this may push the country back to the left in some, though not all, areas.

"The country is gradually evolving into a new reality based on population, demographics, and diversity," says Professor Sabato. "We're going to be a majority minority country, which has tremendous implications for politics."

Still, it seems very unlikely that America will return to a New Deal-type liberalism. If anything, what may be emerging may look more and more like a modified form of libertarianism – in which voters don't want government involved in business or moral issues.

There's some evidence that is already happening. In June, a poll by CNN/Opinion Research Corporation found that 63 percent of Americans said the government was trying to do too much – up from 52 percent in 2008. At the same time, the survey showed that 50 percent thought the government should not favor any particular set of values – up from 41 percent in 2008.

For now, most conservative voters still tend to be conservative on social issues as well as on fiscal matters. But in this election cycle at least, those cultural divisions seem more muted, since economic issues are essentially crowding out everything else.

"If you look at tea party members, they're clearly socially conservative, but they're just not wearing that on their sleeve this election," says Karlyn Bowman, a public opinion expert at the American Enterprise Institute. "The emphasis is clearly on fiscal conservatism."

To some extent, it's as if the conservative movement has come full circle, back to the original ideology of Goldwater.

"Goldwater talked about government being too big, spending too much, regulating too much – and he was also like, 'who cares whether people are gay or straight?' " says former GOP Congressman Mickey Edwards, who entered the House of Representatives in 1976, the same year Hatch joined the Senate. "In the '70s and early '80s, there was great concern among Republicans about spending, but it was overshadowed by a lot of other things – war questions, social questions. And now it looks like finally the size of the deficit has people suddenly saying, 'OK, that's it.' It used to be the issue of economic conservatives, but now it has widespread resonance."