WASHINGTON (Reuters) - How did Democrat Hillary Clinton tumble from all-but-certain presidential nominee to endangered candidate fighting for her political life?

Democratic strategists and political experts say her path to the political promised land has been pitted with potholes. Her campaign suffered from overconfidence, had no answer to Barack Obama’s inspirational call for change, and was unable to control former President Bill Clinton, among other problems.

When she opened her candidacy 13 months ago, she did so with a brash statement: “I’m in, and I’m in to win.” By August, she was the absolute front-runner, enjoying an 18 percent lead in the polls over Obama, her closest challenger.

With her politically brilliant husband at her side, she was considered by Republicans to be the candidate to beat in the November election. She and her aides projected an aura of inevitability and she tried to stay above the fray of her chattering rivals.

Many Washington pundits assumed she would defeat the Republican nominee to win the presidency, with Americans looking to turn the page after eight years of President George W. Bush.

Then voters started confounding the pundits and pollsters.

She lost Iowa to Obama, won New Hampshire, split the February 5 “Super Tuesday” states with Obama and then lost 11 contests in a row to the Illinois Democratic senator.

A day of reckoning is approaching on Tuesday, when Texas and Ohio vote. Anything other than sweeping victories in those two states would spell more trouble for her, and possibly signal the end of her campaign.

Stephen Hess, a presidential scholar and political science professor at George Washington University, said the Clinton team “accepted without question their advance notices.”

“There was a real sense that this was their right,” he said.

‘FUNDAMENTALLY MISREAD’ AMERICAN PEOPLE?

Democratic strategist Jim Duffy said the Clinton campaign “fundamentally misread” the American people, believing Americans would prefer her experience over Obama’s call for sweeping change in the way Washington does business.

“When Obama catches fire they have nothing to come back with because their whole campaign is premised on the fact that they know Washington and how to wheel and deal and get things done,” he said.

“Here’s a man preaching hope and change ... Who wants to be on the other side of arguing against that?”

Democratic strategist Liz Chadderdon said Clinton never really had a single message that was her own and never developed an emotional connection with voters that resonated like Obama did.

“Rule No. 1: Stay on message. At this point, can you tell me what the message of her campaign is? Because I think at this point she has about 90,” Chadderdon said.

“She misread what change means. Change doesn’t mean a change in policy. Change means a fundamental change in how we do politics in this country.”

The experts also said the role of her husband damaged her campaign. For many weeks the former president talked as much about himself as he did her, reminding Americans not only of the good times he brought to the country, but also the bad.

In South Carolina, Bill Clinton angered black voters by saying Obama’s strength there was equivalent to another African-American candidate, Jesse Jackson, who won the state in 1984 and 1988 but failed to win the Democratic nomination.

“I think the Jesse Jackson comment was really rock bottom for him, rock bottom you hadn’t seen in a decade,” said a long-time Clinton supporter, who asked to remain anonymous.

But overall, this Democratic strategist said: “I think that fundamentally she just missed her moment. There’s a lot of people who say she ran a bad campaign, should’ve introduced herself better. But I think fundamentally that her time passed, and that the day Barack Obama got in the race, at some level for both (ex-Democratic candidate John) Edwards and Clinton, it was over.”

(To read more about the U.S. political campaign, visit Reuters "Tales from the Trail: 2008" online at blogs.reuters.com/trail08/)