Facing steep odds and a nasty campaign as one of the nation's most endangered Democrats, Gov. Bev Perdue announced Thursday she is abandoning her re-election bid.

Perdue's departure shocked the North Carolina political establishment, coming as a surprise to top Democrats and even her staff just 15 weeks before the May primary election.

In a statement, Perdue said she wants to focus on improving state education funding and her "re-election will only further politicize the fight."

"Therefore, I am announcing today that I have decided not to seek re-election," she continued. "I hope this decision will open the door to an honest and bipartisan effort to help our schools."

The opening at the top of the Democratic ticket holds national implications and creates a scramble to find a strong replacement in a political swing state that will host the Democratic National Convention and play a key role in President Barack Obama's re-election effort.

Obama issued a statement praising Perdue, the state's first female governor, and congratulating her on her historic tenure. "Bev Perdue has never been afraid to break barriers," Obama said.

First one-term governor

Perdue, one of three Democratic state executives in the South, will be the first North Carolina governor to serve one term since gubernatorial succession was instituted in the 1970s.

For months, Perdue maintained she would seek a second term, hiring five campaign staff members and raising money, even amid sinking poll numbers and the ongoing criminal cases against three campaign associates related to fundraising from her 2008 campaign.

Perdue associates insisted that her decision was not linked to any legal concerns or any pressure from the Obama administration.

But the weak state economy didn't help her fortunes. North Carolina's unemployment rate was 9.9 percent in December - above the national average and virtually unchanged from a year ago.

A recent survey of likely voters from Public Policy Polling, a Democratic firm, showed that half of those polled viewed her unfavorably, making Perdue one of the most unpopular governors in the nation. A hypothetical matchup with likely Republican nominee Pat McCrory, a former Charlotte mayor, put her behind by 11 points. A litany of political observers consistently have ranked Perdue as one of the most vulnerable Democrats in the 2012 election.

Perdue beat McCrory in 2008 by the closest margin in a governor's race since 1972, outspending him substantially. But her re-election campaign couldn't match her previous fundraising benchmarks, and some top donors began defecting to McCrory.

Both candidates reported about $2 million in cash at the start of the year. It's unclear what Perdue will do with her money. In her announcement Thursday, Perdue said she enjoys fighting for her causes and doesn't "back down from tough fights."

But as it became harder to raise money in recent months and her poll numbers worsened, Perdue, who turned 65 on Jan. 14, began to have second thoughts in recent weeks, according to campaign associates and friends.

Halftime crowd booed

As the election neared, it became evident that third-party groups associated with the Republican Governor's Association and other conservative organizations were poised to spend millions of dollars in personal attack ads that questioned her ethics and her family. And earlier this month, Perdue and her campaign became rattled after the crowd at a UNC basketball game in Chapel Hill booed when she was introduced at halftime, friends said.

"I noticed the other day she looked tired on TV," said Kaye Gattis, chief of staff when Perdue was North Carolina's lieutenant governor, from 2000-2008. "It's a tough environment right now."

With the odds against her, Perdue could only win with an onslaught of negative ads attacking McCrory. And even amid the mudslinging, there was still a strong chance she would lose.

The governor spent the weekend re-evaluating her campaign, a friend said. She felt she could still win. Her campaign released a memo Thursday from her pollster that showed her only behind six points and which said that McCrory's support was "exceptionally soft."

"There was a path to victory - a narrow path and she would have had to thread the needle and have a harmonic convergence," said Ken Eudy, a former state Democratic Party executive director and Perdue fundraiser.

Earlier this week, Perdue made her decision not to run. On Tuesday, she began holding a series of conversations with key aides in North Carolina and Washington. Rumors began Wednesday and seemed confirmed later that day when the campaign canceled a statewide finance committee meeting, aides said.

But she kept the decision from most of her office staff and campaign aides, as well as prominent Democratic Party leaders, until Thursday morning.

At noon, she issued her statement: "In my remaining months in office, I look forward to continuing to fight for the priorities we share ..."