ANALYSIS-How can Republicans win the US presidency now?

(Updates headline, second paragraph)

WASHINGTON, Jan 23 (Reuters) - A tottering U.S. economy, an unpopular Iraq war, eight years of Republican control of the White House -- it all adds up to a Democratic lock on the presidency in November's presidential election. Right?

Well, maybe not.

Many Democrats and political experts believe the Democrats have a natural advantage this year, with a "throw-the-bums-out" clamor for change sweeping the country after two terms of President George W. Bush.

The warning signs for Republicans are apparent in the turnout numbers so far from some of the early contests in the state-by-state battles to determine which Democrat and Republican will face off in the November election to succeed Bush.

In Iowa, New Hampshire and Nevada, Democratic turnout doubled the Republican tally, suggesting a higher level of enthusiasm on the Democratic side in what is the most wide-open presidential election of the past 50 years.

"I think it's going to be a very steep uphill climb for the Republicans because the Iraq war, while steadied by the surge, is five years old with no end in sight and the economy is headed south," said Cal Jillson, a professor of political science at Southern Methodist University in Dallas.

In the past 50 years, the only time a party has hung on for a third presidential term was when Republican Ronald Reagan won two terms and was succeeded by his vice president, George H.W. Bush, who left office 15 years ago.

But there are plenty of people who think Republicans can beat the historical odds. Take a look at this survey, for instance:

A CNN/Opinion Research Corporation poll asked voters who has the personality and leadership qualities to be president. Republican John McCain had 60 percent, Democrat Barack Obama had 59 percent and Democrat Hillary Clinton had 55 percent.

"The presidential race now looks like a toss-up -- perhaps even with a Republican edge," Paul Starr, co-editor of the liberal American Prospect magazine, wrote in The Washington Post on Sunday. "If Democrats don't stay smart, tough-minded and realistic, we could blow it yet again."


There are plenty of reasons for doubt on both sides.

New York Sen. Clinton is viewed negatively by a large segment of voters not anxious to return the Clintons to the White House. Illinois Sen. Obama has made a compelling case for change but has little foreign policy experience.

On the Republican side, former Massachusetts Gov. Mitt Romney has economic experience as a wealthy venture capitalist but not much on national security. Arizona Sen. McCain has a foreign policy and national security background but is not an economic expert.

Still, Republicans think they stand a good chance and liked the bickering debate on Monday night between the Democrats' leading candidates, Clinton and Obama.

"Republicans need to encourage the television networks to host more and more debates, because every time these two go at it like they did Monday night it turns off Democrats, it turns off independents and it turns on the Republicans," said Republican strategist Scott Reed.

Bush's troop build-up, or "surge," has achieved some stability in Iraq, removing the war from the top of the list of voter concerns.

Voter attention is now on the U.S. economy, buffeted by a housing market that is threatening to tip the country into an election-year recession.

"If the economy is sliding into a recession that would favor the Democrats," said Andy Smith, political science professor at the University of New Hampshire.

But a campaign about national security would favor Republicans, he said, particularly if Republicans nominate McCain, a former Vietnam prisoner of war and a critic of Bush's handling of the Iraq war.

McCain's history of bucking the Republican establishment at times could help him in a general election campaign, his supporters believe.

"If you looked at every dynamic in past political history, it should be a Democratic year," said South Carolina Republican Sen. Lindsey Graham. "But I think the unusual times in which we live will defy convention, and it is clear to me that John McCain is the biggest threat to Democratic hopes of capturing the White House because he puts (Democratic) states in play." (Additional reporting by Ed Stoddard) (Editing by David Alexander and Cynthia Osterman) (For more about the U.S. political campaign, visit Reuters "Tales from the Trail: 2008" online at http:/