WASHINGTON (Reuters) - The 2012 presidential election is more than six months away, but here is what we know so far: It is going to be close, it is going to be nasty, and the outcome could turn on a series of unpredictable events.
Democratic President Barack Obama is a slight favorite now, but as tightening poll numbers suggest, his lead over Republican Mitt Romney is tenuous.
A tepid economic recovery, voter pessimism about the future and a job approval rating largely stuck in the danger zone below 50 percent mean Obama could have a hard time matching his performance in 2008, when enthusiasm for his promise of change propelled him to victory over Republican Senator John McCain with 53 percent of the vote.
Such factors, along with a motivated Republican Party determined to oust Obama, mean that despite a bruising Republican primary fight that dented Romney's popularity - particularly among women - the Republican has plenty of reason for hope in the November 6 election.
Political analysts see a fall election fight that looks more like the nail-biters won by George W. Bush in 2000 and 2004 than Obama's relative blowout victory in 2008.
Three-quarters of American voters still think the economy - the top election issue by far in most polls - is in a recession, a recent ABC/Washington Post survey found, and more voters trust Romney to deal with the economy than Obama.
Polls also routinely indicate that more than six of every 10 voters think the nation is on the wrong track, a critical and closely watched measure of the collective American psyche.
"Most Americans think they are worse off now than they were four years ago, and that's not what an incumbent president wants to see," Quinnipiac University pollster Peter Brown said.
He compared Obama's burden in defending his economic leadership with former President George W. Bush's 2004 struggle to defend the Iraq war. Bush narrowly won re-election that year over Democrat John Kerry in a race dominated by debate over the U.S.-led invasion of Iraq.
"This race looks a lot more like 2004 than 2008," Brown said. "The economy is Barack Obama's Iraq war. The 2004 election was a referendum on the Iraq war, and 2012 is going to be a referendum on the economy."
Romney, the former governor of Massachusetts, has seen a slight improvement in his poll ratings since Republican rival Rick Santorum suspended his campaign last week and cleared Romney's path to the party's nomination.
A Reuters/Ipsos poll this week showed Obama's lead had shrunk to 4 points from an 11-point advantage in early March. A new CBS News/New York Times poll has the race in a dead heat, with Obama and Romney each at 46 percent.
Gallup's daily tracking poll on Monday gave Romney a 2-point edge over Obama, who had led by four points in late March.
A presidential candidate's standing in April, however, is not always a sign of things to come.
An April 1992 Gallup poll gave President George H.W. Bush a 15-point lead over the eventual winner, Democrat Bill Clinton. In April 1980, President Jimmy Carter led Republican Ronald Reagan by 8 percentage points. Reagan ultimately won by 10.
Complicating the outlook is looming uncertainty about the pace of the economic recovery, highlighted by a disappointing March jobs report and high gas prices.
Those factors, as well as economic instability in Europe that could spill over to the United States, and the potential for a foreign crisis just before the election, cloud Obama's path to victory in November.
"Obama has better personal ratings than Romney for now, but that may not matter if the economy is in bad shape, if North Korea engages in provocative actions, if Iran is enriching uranium and there is a possibility of war in the Middle East - all of those don't bode well for an incumbent," Democratic pollster Doug Schoen said.
An Israeli military strike aimed at disrupting Iran's nuclear weapons program would be the type of crisis that can shift an election in unpredictable ways - much as the Wall Street crisis in September 2008 helped power Obama into office.
"Iran could be a real wild card. All bets are off if that happens. You don't know how Obama's reaction would be viewed; it could work for or against him," said Steven Schier, a political scientist at Carleton College in Minnesota.
"In many ways, neither campaign is really in charge of their own fate. A lot of things can go wrong for both Obama and Romney," he said.
Romney must still work to shore up his support among conservatives who mistrust him for some of the stances he took as governor of liberal Massachusetts, including his backing of a state healthcare overhaul that became a precursor to Obama's federal plan.
But recent polls show the burning desire of conservatives to kick Obama out of the White House is rallying Republicans.
In the end, the election is likely to be decided by a relatively small bloc of undecided, independent voters in fewer than a dozen battleground states.
A recent poll of those swing voters by Third Way, a centrist think tank, found they viewed Obama as more likable but thought Romney's center-right views were closer to their own.
"The middle really and truly is up for grabs," said Lanae Erickson, deputy social policy and politics director at Third Way. She noted independents went for Democrats in 2008 and switched to Republicans in the 2010 midterm elections.
"They are looking for something and they really haven't found it yet," Erickson said. "We have a lot of people who are really swinging around, and the ones who have made up their minds are split."
The combination of Romney's weaknesses and Obama's vulnerabilities also make it likely each camp will spend heavily on negative advertising designed to tear down its opponent.
Analysts say that between the campaigns and the independent "Super PACs" that support them, spending in the presidential race is likely to total well over $1.5 billion.
Both sides have begun the onslaught, with Obama and his Democratic allies portraying Romney as wealthy and out of touch with typical Americans, while Romney attacks Obama as a big-government liberal.
Republican pollster Whit Ayres said it was crucial to Obama's hopes for victory to keep the election from becoming a referendum on his performance.
"Barack Obama could not win a referendum on his record today," Ayres said. Democrats "have decided their only route to re-election is to so thoroughly trash Mitt Romney as to make him an unacceptable alternative."
Romney is familiar with that tactic: His most significant victories in the state-by-state primary process came after his campaign and a pro-Romney PAC put out a barrage of ads attacking Romney's rivals.
On the economy, Obama argues that his policies prevented broad chaos, steadied the nation's banking and financial system and rescued Detroit's auto industry.
Romney focuses on the slow recovery, growing budget deficits and what he says is an explosion in government regulation and overreach, climaxed by the unpopular healthcare overhaul.
In the end, analysts say, the election could turn less on economic indicators and more on how optimistic voters feel about the future.
"What will matter in November is whether people think their lives will be better off with four years of Mitt Romney or four more years of Barack Obama," Brown said. "Right now, it's a jump ball."
Editing by David Lindsey and Peter Cooney