WASHINGTON (CNN) -- In politics, as in life, there are no sure bets. But Sen. Hillary Clinton came close.
Sen. Hillary Clinton, once the "inevitable" Democratic nominee, will formally end her presidential bid Saturday.
Her official announcement to run for president was a formality on the way to a nomination that seemed so certain Republicans spent much of 2007 publicly debating which candidate was best-equipped to run against the senator from New York.
Clinton had a lengthy list of seemingly insurmountable advantages, but three factors in particular made her a lock: One was her husband, the former president who still hovers around the top of the list of most admired chief executives and influential Democrats.
Another was a decades-long stint in the public eye, including her husband's two terms in the White House that made for a reassuring portrait of a veteran hand at the helm.
Months before she declared her candidacy, the adjective that appeared most often in descriptions of the former first lady's campaign was "inevitable." Watch a top Clinton supporter discuss the race »
But once the race began, those advantages rapidly evolved into chronic, near-unfixable vulnerabilities.
Her image as a tested leader left her open to attacks on two fronts: from those who questioned the extent of that experience -- and from the overwhelming majority of Americans who told pollsters they were eager for wholesale change.
The thought of a Clinton following a Bush following a Clinton following a Bush hardly seemed to fit the national mood.
Her vote in favor of the bill authorizing the use of force in Iraq seemed like a prudent move at a moment when her biggest concern was boosting her appeal to independents in the general election.
But as 2007 drew to a close, the sentiment of most of the public -- and the entire activist base of her party -- had shifted overwhelmingly against the war in Iraq.
Clinton's efforts to stress her credentials as a fighter -- and her years of experience taking on the "Republican attack machine" -- may have resurrected baggage stowed in the nation's collective memory.
Before the race began, the '90s were remembered as an era of plummeting crime rates and soaring opportunity, when jobs seemed plentiful and the deficit disappeared. Clinton's rhetoric revived messier memories: of unmatched partisan warfare and the biggest battle of all -- the impeachment of her husband and his affair with a White House intern.
Bill Clinton, who entered the year with a reputation as the greatest campaigner of his generation, seemed to be a bit out of step with the national mood.
He spoke like a politician with nothing to lose, and his confrontational comments on the trail alienated supporters and undecideds alike. He stole headlines from his wife and regularly threw her team into triage mode, raising concerns over his outsized influence and contributing to the impression that a vote for her would be a ballot for restoring a de-facto Bill Clinton presidency.
After a third-place finish in Iowa stunned her campaign, the former president shifted from chief optimist to attack dog, with remarks that drew fire from many African-American leaders and alienated much of that community -- along with moderate swing voters.
As Sen. Barack Obama's fortunes rose, Hillary Clinton's support from black voters virtually disappeared. And whispers over Bill Clinton's post-presidential income and associations hovered over the race.
Those challenges might have been overcome -- if the organization she gathered around her hadn't failed her in nearly every respect.
She let star hires such as Steve Hildebrand, now Obama deputy campaign manager, slip through her fingers in favor of longtime loyalists with questionable track records -- such as campaign manager Patti Solis Doyle and controversial strategist Mark Penn. She held on to these aides long past the point when they moved from near-ineffectiveness to outright liability.
Penn's poll-crafted message of inevitability flopped, and under his direction her likability ratings plummeted. Alarmed, her campaign went on a seemingly frantic journey from one new slogan to the next -- most driven not by her agenda but reaction to Obama's rise.
Under Solis Doyle -- who had managed a virtually unopposed Clinton Senate re-election bid that somehow burned through tens of millions of dollars -- a massive cash advantage evaporated soon after voting began.
Accounts of deep staff divisions and raging internal turmoil became a staple of Clinton campaign coverage, and competing staff leaks and stories of profanity-laced tirades between senior advisers contributed to the impression of a campaign spiraling out of control.
The decision to compete in the Iowa caucuses -- despite a cautionary internal memo counseling her to skip the contest -- may have been one fatal error.
A defeat there shattered the aura of inevitability and sent the campaign into a tailspin from which it never fully recovered.
A campaign built for a sprint -- which regularly predicted the race would be over by the first week in February -- found itself instead in a high-stakes marathon. Senior advisers dispatched ground-game gurus such as Michael Whouley and Ace Smith on missions to unexpectedly threatened or newly critical states -- only to discover grass-roots, Web-driven Obama efforts firmly established.
As resources dwindled, manpower-intensive caucus states were abandoned in favor of delegate-rich primary battlegrounds, a critical error that allowed Obama to amass a pledged delegate lead that Clinton was never able to overcome.
Every contest turned into a potential Waterloo for the Clinton team as it lived to fight another day, only to find itself on the defensive in a new set of contests with equally massive odds and do-or-die stakes. Her campaign spiraled into a multimillion-dollar deficit that increasingly limited its options.
By the end, Clinton was operating at half-strength: In most states, Obama had double or triple the field offices she had and often four to five times the ad budget.
As media coverage of Clinton's candidacy shifted to reflect the new realities of the race, her campaign started to develop a hostility that permeated the entire organization and proved a distraction from far more daunting challenges.
At the top, former President Clinton publicly and privately railed against what he called "the most biased coverage in history," and both Clintons complained of what they believed to be a pervasive sexism dominating the campaign narrative.
On campaign conference calls, a new press skepticism to ever-evolving standards of electoral success was often met with outright antagonism from Clinton staffers.
Clinton herself made major missteps based in large part on her dedication to longtime campaign strategy. With her dedication to the experience theme, she emphasized her government service in language that invited scrutiny, with descriptions of Bosnian sniper fire, high-level security briefings and key roles in international policy decisions during her time as first lady.
The first woman with a serious shot at a major-party presidential bid faced challenges unlike any other: public demands to show emotion without appearing emotional, to demonstrate willingness to compromise and admit error without appearing weak.
Clinton struggled to navigate the minefield. Some of her toughest attacks on Obama struck a sour note. And her emotional response to an audience question on the eve of the New Hampshire primary -- widely credited with propelling her to victory -- proved just as controversial, a sort of Rorschach test of Clinton's sincerity for much of the Democratic electorate.
Policy contortions and unexpected reversals, such as her backtrack on the issue of drivers' licenses for undocumented immigrants, hurt her. So did her reluctance to admit error, as many primary voters urged her to do over her Iraq war vote.
The first stirrings of Obama's momentum were visible before the race began, but no campaign could have predicted his rapid, seemingly unstoppable rise. Much of the Democratic electorate found itself drawn to the party's first African-American candidate with a serious shot at the presidency.
As young voters began showing up at the polls in significant numbers and key Democratic blocs such as black voters and the college-educated flocked to his candidacy, the beginnings of a party schism began to take shape.
Amid record turnout, Clinton and Obama roughly split the popular vote -- but some of her appeals to white, working-class voters in later contests drew sharp disapproval from Democratic Party leaders. And her campaign's adoption of the language of the civil rights era to press for the full seating of delegates in the unsanctioned contests in Florida and Michigan further alienated key officials and many voters.
The senator from Illinois proved the near-complete counterpoint to Clinton: weak where she was strong, strong where she was weak. Watch more on Clinton's presidential bid »
Unfortunately for Clinton, Obama's highest marks came in an area -- which candidate was viewed as most likely to deliver change -- that continues to top the voter agenda this cycle. Even his disciplined, near-leakproof campaign organization seemed a total contrast to the freewheeling, chaotic image of the Clinton effort.
Democratic icons such as Sen. Edward Kennedy and former Clinton loyalists such as New Mexico Gov. Bill Richardson began to back Obama, with their announcements driving potentially damaging headlines off the nation's front pages at critical moments in his campaign.
Last fall, nervous Republicans fretted over their difficulty settling on a candidate best-suited to take on Clinton, who was assumed to have a lock on her party's presidential nomination.
But by spring, the roles were reversed, as anxious Democrats worried over the delay in selecting which standard-bearer would be most likely to beat Sen. John McCain, the presumptive Republican nominee.
Eventually, inevitability returned to the Democratic presidential contest. But it no longer belonged to Hillary Clinton.