What in the world is the matter with the Republican Party?

This is an election year when pretty much everything should be going the GOP’s way.

A Democratic president is facing the worst reelection environment in a generation. The conservative base is fired up to defeat him and should be riding high after securing the largest GOP House majority since the 1940s. Looser campaign finance restrictions have unleashed the ability of the party’s wealthiest donors to spend unlimited amounts.

But instead of a smooth ride, the party is experiencing the bumpiest presidential primary season in anyone’s memory, one that has at times seemed more a carnival than a coronation. It is all happening at a moment when the party knows it has little margin for error, given its fervor to bounce President Obama from office and its desire to incorporate the burgeoning tea party movement into the GOP fold.

The latest bump came last week, when former Pennsylvania senator Rick Santorum won three contests in a single night, a surprising sweep that revived his flagging candidacy and — once again — ignited angst about front-runner Mitt Romney and whether the party would ever unite.

Given Obama’s vulnerability, “it’s a nomination worth getting, but nobody’s really satisfied with who is in the field,” said Matthew Dowd, who was a top campaign strategist for George W. Bush. “There are these real fissures in the party now, and nobody is capable of unifying them.”

The old cliche has it that when it comes to picking their candidates, Democrats fall in love while Republicans fall in line. But this year it would seem that Republican voters are doing neither.

The GOP rank and file have a palpable lack of enthusiasm for Romney, who thus far has lost more states — five — than he has won — four.

Meanwhile, turnout has begun to fall off as the tone of the race gets uglier.

The GOP’s image is also taking a beating. In the latest NBC News-Wall Street Journal poll, respondents expressing strongly negative feelings about the GOP outnumbered 3 to 1 those with strongly positive feelings. They aren’t thrilled with the Democrats, either, but the intense animosity is not running nearly as high.

Party leaders say that turmoil and division within the Republican ranks is nothing new — that, in fact, it’s how the party has evolved and grown. Along with the growing pains, however, have come some lost elections.

In a speech last week at the Ronald Reagan Presidential Library, celebrating what would have been the former president’s 101st birthday, former Mississippi governor Haley Barbour noted that as far back as 1912, Democrat Woodrow Wilson was elected because he “got to run against two Republican presidents, Theodore Roosevelt and William Howard Taft, so great was the rift within our party.”

And in the decades since, the party has split into wings as often as not — Thomas E. Dewey’s vs. Robert A. Taft’s; Nelson Rockefeller’s vs. Barry Goldwater’s; Gerald Ford’s vs. Reagan’s.

What’s troublesome now, Barbour said, is that “some voters are seeking purity in their choice. In politics, purity is a dead-dog loser. You need unity, and purity is the enemy of unity.”

So what is happening to prevent the party from coalescing? GOP veterans say there are at least five forces at work: unsettled voters, lackluster candidates, muddled messages, an unprecedented inflow of money, and new rules that have prolonged the race.

The voters

“As conservatives and tea party folks,” Santorum said Friday in a speech at the Conservative Political Action Conference, “we are not just wings of the Republican Party. We are the Republican party.”

With the rise of the tea party and its growing influence, the GOP has shifted to the right. In recent Washington Post-ABC News polls, fully three in 10 Republicans now identify themselves as “very conservative,” up from 22 percent in 2010. And of those very conservative voters, nearly half describe themselves as strong supporters of the tea party.

What remains to be seen is whether they will change the Republican Party — or the party will change them.

The relationship within the GOP family is not an easy one, given that tea party members blame the Republican establishment, along with the Democrats, for much of what they see as wrong with Washington: excessive spending, special deals such as earmarks, bailouts such as the rescue of Wall Street that was instigated under the administration of George W. Bush.

For many tea party members, compromise sounds a lot like selling out. Their demand for ideological fealty and consistency has made it harder for Republicans to govern.

However, incorporating a major new voting bloc is not an unprecedented challenge for the Republicans.

Many senior Republicans see in the tea party parallels to the fiscally conservative Ross Perot voters of 20 years ago. They helped cost George H.W. Bush reelection in 1992, but they swung hard for Republican candidates in the midterm election of 1994 and helped them take over the House for the first time in four decades.

Earlier than that, Barbour said, “we brought into our party millions of Southerners, all of whom had grown up in Democratic households. We brought into our party millions of Midwestern and Northeastern Catholics,” another group that had for generations voted only Democratic. “Making fully active Republicans out of the tea party people is easier than that,” Barbour said, “because they are so much closer to the middle of Republican policy beliefs of long, long standing. They’re not leaving a long historical or family connection, like so many people did in the ’60s, ’70s or ’80s.”

There is another force at work within the party this year: Ron Paul and his hordes of devoted followers. In 2008, the party made no space for Paul’s supporters at the GOP convention in St. Paul, Minn., so they held their own nearby. They called it “Ronstock ’08.”

This year, when the party convenes in Tampa, Paul is all but certain to be given a prime-time speaking spot.

Not since Reagan in 1976 has the voice of an also-ran been so influential, some Republicans argue, because the party needs the energy that his supporters can bring. Romney in particular has been noticeably solicitous of Paul’s goodwill.

Ron Paul is the only Republican whose endorsement matters in turning out voters in the general election,” said anti-tax activist Grover Norquist. “He’s building a wing of the modern Republican Party.”

The candidates

“Everybody wants to defeat Obama — very, very badly,” said former senator John C. Danforth (R-Mo.). But, he said,“we have a cast of characters who are seeking the nomination, and none of them appears to most Republicans to be absolute standouts.”

Danforth has endorsed Romney.

Nothing would do more to solve the problems of the Republican Party, many believe, than a single leader of Reaganesque charisma and vision.

“There are a lot of people still searching for what is that combination of things it will take to win in November,” said Tom Griscom, a longtime aide to former Senate majority leader Howard H. Baker Jr. (R-Tenn.) and White House communications director in the latter years of the Reagan administration. “They haven’t found it yet.”

As the election season rolls on, Republicans may be growing less enchanted with their choices.

In a Pew Research Center poll released late last month, 46 percent of Republicans and Republican-leaning voters rated the GOP field as excellent or good; 52 percent said it was poor or fair.

The figure was almost an exact reversal of how such voters felt shortly before the New Hampshire primary in early January, when just more than half thought favorably of the Republican candidates. And it marked a steep decline of 22 points from four years ago, when 68 percent said they liked the GOP field.

One factor at work is the increasingly brutal and personal attacks the candidates and their super-PAC supporters have been making upon each other. Of the 11,586 television ads aired during the Florida primary, for instance, more than nine out of 10 — a record — were negative, according to data compiled by Kantar Media’s Campaign Media Analysis Group.

Another force at work is what Norquist calls “a meaningless drive for purity” on the part of many GOP voters.

That may sound ironic, given that Norquist is known as a stickler on that subject. He is the father of an anti-tax pledge, signed by virtually every Republican House and Senate member and all four of the remaining presidential candidates, that declares that they will never, under any circumstances, raise taxes on anyone.

But now that they have met his own litmus test, Norquist said of the GOP field: “In point of fact, every one of these guys would be acceptable. There’s much more agreement than there was before.”

The party also finds itself in something of a generation gap.

“All the old guard have fingerprints on earmarks, fingerprints on [the financial bailout of 2008] and Fannie Mae and Freddie Mac,” the government-controlled mortgage giants that many conservatives blame for the financial crisis, Norquist said.

But he added, “You can see coming up around the country a crop of leaders that are Reaganesque.” Among them, Norquist cited governors such as Scott Walker of Wisconsin, Chris Christie of New Jersey, Bobby Jindal of Louisiana and Rick Snyder of Michigan.

“You can see greatness in them,” Norquist said, “but you wouldn’t choose them for quarterback right now.”

The message

For all their desire to beat the president, many in the party argue that it will not be enough just to present themselves as not-Obama.

Republicans “need to have a clearly identifiable agenda or message of what they would do differently,” said former Senate majority leader Trent Lott (R-Miss.), a Romney supporter.

Some of the rising stars in the party agree.

“When I came to Washington, I didn’t come there just to stop President Obama,” said Sen. Kelly Ayotte (R-N.H.), who was elected in 2010. “It’s important for us to present a clear alternative and show what we would do if we were in charge.”

The need to do that has been made all the more urgent by the fact that Republicans have lost their edge on issues that matter the most to them. On the question of who to trust on taxes and spending cuts, for instance, Republicans in Congress poll roughly even with Obama.

But many of their ideas — such as the plan put forward by House Budget Committee Chairman Paul Ryan (R-Wis.) to overhaul Medicare — could be difficult to sell to general-election voters. That is why many Republicans would just as soon wait for a presidential nominee, in hopes that he will set the agenda.

Lott, however, argues that there is precedent for Congress stepping up early, noting that “a lot of what Reagan ran on came out of the House and was pushed by Jack Kemp,” the congressman from New York who was an early and ardent champion of supply-side economics.

The money

Republicans celebrated two years ago when the Supreme Court issued a ruling that allowed groups, corporations, unions and individuals to spend unlimited amounts on campaigns, as long as those efforts were not coordinated with the campaigns.

They now realize that the new unregulated money is one of the main reasons, whether for good or bad, that the race continues and remains so unpredictable.

Before that ruling, when a campaign ran out of money, the candidate usually dropped out. Fundraising networks were also the tool by which the establishment bestowed its benediction upon a favorite contender and crowded everyone else out.

The most spectacularly successful example of that strategy in recent years was the one employed in 2000 by George W. Bush and the “Pioneers,” who each committed to raise $100,000 toward his election. They did it the old-fashioned way, by bringing in 100 checks for $1,000 each.

But that kind of money looks like chump change compared with, say, the $11 millionthat Las Vegas casino mogul Sheldon Adelson and his family have donated to a super PAC that supports Newt Gingrich. Without those contributions, it is hard to see how Gingrich’s candidacy would be alive today.

The super PACs have also contributed to the unprecedented negativity of this primary season. Because candidates do not have to stand behind what is said in super PAC ads, they have hit their rivals much harder than any campaign would dare.

In Iowa, the pro-Romney super PAC spent $3 million tearing down Gingrich with advertising that accused him, among other things, of having “more baggage than the airlines.” In South Carolina, the pro-Gingrich super PAC went after Romney’s wealth, waging what some Republicans criticized as the kind of class-warfare attack they might have expected from Occupy Wall Street.

The candidates have expressed dismay over what their own allies are doing.

“That’s something which is completely out of the control of the candidates,” Romney said in a debate in Myrtle Beach, S.C., last month. “One of the things I decry in the current financial system that gets behind campaigns is that we have these voting requirements that put these super PAC’s in power that say things we disagree with.”

Still, neither he nor any of the other candidates has called upon the super PACs that support them to cease fire. And after criticizing the Supreme Court decision, Obama recently gave his blessing to a super PAC that supports him.

“Our campaign has to face the reality of the law as it stands,” Obama campaign manager Jim Messina told supporters.

The calendar

In an interview Saturday with CNN and the New York Times, 2008 vice presidential nominee Sarah Palin said she would like to see the race continue right into the convention this summer.

“I don’t think that it would be a negative for the party, a brokered convention,” said the former Alaska governor. “And people who start screaming that a brokered convention is the worst thing for the GOP, they have an agenda. They have their own personal or political reasons for their own candidate, who they would like to see protected away from a brokered convention. That’s part of the competition. That’s part of the process. And it may happen.”

A long and arduous primary is not necessarily a bad thing. Republicans often point to the 2008 race between Obama and then-Sen. Hillary Rodham Clinton that dragged on until June. It is generally believed that the lengthy battle strengthened Obama for the fall, making him a better candidate and helping him build an organization that spanned the country.

Republican leaders were hoping to see something similar in their party this time.

“When the process was set out, they wanted this to happen,” Republican National Committee spokesman Sean Spicer said.

This year, the Republican race started much later than it had in the past, leaving the field unsettled almost into the fall. The last major contender to enter the race, Texas Gov. Rick Perry, did not make his announcement until August.

And the party wrote its rules so that no one could win the nomination — which takes 1,144 delegates — with an early knockout punch.

In the first round of primaries and caucuses, for instance, most states are required to award their delegates proportionally, rather than in the GOP’s traditional winner-take-all manner. Some of the states have balked at that and are likely to lose some of their delegates as a result.

But the rules give the candidates far more flexibility to pick their battles — as the underfinanced Santorum did last week, when he swept the contests in Colorado, Minnesota and Missouri. And in doing so, he guaranteed that the long GOP race, with all of its turmoil and consequences for the party, will continue.

Polling analyst Scott Clement contributed to this story.