

At an event that was long past his campaign's expiration date, Newt Gingrich ended his presidential campaign at a press conference Wednesday afternoon in Virginia.

"Today I am suspending the campaign, but suspending the campaign does not mean suspending citizenship," Gingrich said. He thanked Rick Perry, Herman Cain and casino mogul and super PAC donor Sheldon Adelson, among others.

Gingrich said of South Carolina, where he won the Republican presidential primary, that he had "broken their tradition of always picking the nominee" and will always feel "slightly guilty" when traveling there.

At the end of his remarks, he tepidly endorsed the presidential candidacy of Mitt Romney. "I'm asked sometimes, Is Mitt Romney conservative?" Gingrich said. "And my answer is simple: Compared to Barack Obama? This is not a choice between Mitt Romney and Ronald Reagan. This is a choice between Mitt Romney and the most radical leftist president in history."

Although Romney has not yet reached the number of delegates needed to officially clinch the Republican presidential nomination, he became the presumptive nominee weeks ago, when former Pennsylvania Sen. Rick Santorum announced an end to his candidacy. Gingrich, however, stayed on course, while his campaign drowned in debt and his chances for the nomination dropped to near zero.

From when he first announced his intention to run in May 2011 through his triumphant win in the South Carolina primary, Gingrich insisted that his mastery of conservative issues and his vast legislative experience was enough to beat President Barack Obama, but he failed to capture the support of the Republican primary electorate.

While Tim Pawlenty and Michele Bachmann of Minnesota rode high in the summer of 2011, Gingrich was written off as a pretender. When Texas Gov. Rick Perry branded himself as the conservative alternative to former Massachusetts Gov. Mitt Romney, Gingrich trudged on.

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"There are lots of bunny rabbits who run through," Gingrich would later say. "I am the tortoise. I just take one step at a time."

Gingrich began his presidential journey with some confusing reversals on major issues: In March 2011 it appeared the nation was about to engage in military action in Libya; Gingrich urged President Obama to get involved. But when the United States sent air support to Libya, Gingrich criticized the president, saying he would not have engaged.

In May of last year, Gingrich was a vocal opponent of Republican House Budget Chairman Paul Ryan's Medicare reform proposal, calling it "right wing social engineering." When he subsequently apologized, he said anyone who quoted his comments was acting dishonestly.

Gingrich was also criticized for his personal life in the campaign's early days: Politico reported that Gingrich at one time personally owed hundreds of thousands of dollars to the jewelry store Tiffany & Co (financial disclosure forms showed the debt had been paid in full.) He also briefly put the campaign on hiatus so he could take a luxury cruise in Greece with his third wife, Callista.

Gingrich repeatedly stressed that he would ultimately be the nominee. His stump speeches focused not on the other candidates in the race, but on his own ideas for changing Washington, rather than, as he put it, "managing the decay." At the 2011 debates, where Gingrich shined, he refused to attack fellow Republicans when given the opportunity, channeling his vitriol toward Obama, or even the debate moderator.

It wasn't until the end of 2011, when hopes for Herman Cain faded amid allegations of sexual harassment, that many Republicans began to give Gingrich a serious look. With Cain's popularity on the decline, Gingrich's poll numbers skyrocketed.

By that point, several of the staff members who abandoned him in June for other campaigns had returned. "It's good to have some old friends come back," Gingrich's spokesman R.C. Hammond said at the time. But the campaign suffered from the lack of staff and resources--Gingrich did not establish an office in Iowa until mid-December.

In the weeks leading up to the caucuses, Gingrich vowed to run what he called a "solutions-oriented campaign" and refrained from negative attacks on his opponents. But when he came in fourth place in the Iowa caucuses Gingrich changed his strategy. From then on, he played offense. And with decades of practice battling Democrats in Washington, he was exceptional at it.

From the moment he touched down in New Hampshire in January, Gingrich, who for months had held his tongue--something he admitted was not an easy thing for him--unloaded on his rivals. He directed most of his attacks at Romney, whose allies had spent millions trying to bring Gingrich down in a nasty, and successful, ad war.

On the trail in New Hampshire, Gingrich hit Romney from every angle: criticizing him for his management of Bain Capital, calling him a "Massachusetts moderate" (and later, a "liberal"), and knocking him for implementing a health care plan as Massachusetts governor that included an individual mandate for state residents to purchase insurance. He also told supporters that Romney implemented a tax on the blind and later misleadingly told voters that Romney tried to block Holocaust survivors from receiving kosher meals in Massachusetts nursing homes.

After failing to place among the top three finishers in New Hampshire, Gingrich's meteoric rise appeared to have stalled. That would all change when he won the next contest in South Carolina, a victory that breathed life--and much-needed cash--into his campaign.

Gingrich won South Carolina by a wide margin. Unfortunately, his southern victory would mark the highest point in his campaign. He wouldn't win another state besides Georgia, which he represented in Congress for two decades.

On the campaign trail, Gingrich mastered the art of targeting local issues, confidently offering voters state-specific answers. He employed this strategy with such frequency that Romney criticized him for pandering. When a man expressed concern during a Manchester town hall about veterans' access to medical services, the Gingrich campaign drew up a plan that day to build hospitals in northern New Hampshire. Gingrich presented it at a rally that evening.

The strategy reached what many perceived to be a comedic tipping point in Florida, where Gingrich unveiled an ambitious plan for space exploration. During a speech along Florida's central coast, where thousands of jobs rely on the space industry, Gingrich vowed to build a colony on the moon by his second term, and promised to make exploration a priority. His opponents pounced, claiming Gingrich's priorities were misguided.

Meanwhile, former Pennsylvania Sen. Rick Santorum, who bested Romney in Iowa, was steadily on his way to replacing Gingrich as the "conservative alternative" in the race.

After Super Tuesday, it became clear that Gingrich would not be able to achieve the delegates needed to win the nomination. Despite calls for him to leave the race, Gingrich soldiered on, and briefly helped leave open the possibility of a contested Republican convention.

Soon, the calls for Gingrich to step down grew louder and his debt burden grew larger. Sheldon Adelson, the billionaire casino mogul who had bankrolled super PAC ads supporting him, announced he would stop writing checks.

Gingrich, who perhaps did for a short time--as his former spokesman dramatically put it last year--rise "out of the billowing smoke and dust of tweets and trivia," shrunk back out of the spotlight as Romney accepted the title of Republican nominee. Gingrich refused to step down, hanging on for several weeks after Santorum ended his candidacy.

Finally, after a five-state primary in April, Gingrich made the decision to concede to Romney.

On Wednesday, Gingrich said he and his wife will maintain their "focus on a series of key issues and try to find way to move forward" on matters like energy, "American exceptionalism and American history," balancing the budget, brain science and space exploration.

"I am cheerfully going to take back up the issue of space," said Gingrich, who was mocked by some for his proposal to establish a permanent American base on the moon by 2020.

"I thought, frankly, in my role providing material for 'Saturday Night Live,' it was helpful," he said. More seriously, he added, "If we are going to be the leading country in the world," the United States must also be the leading country in space exploration.

This story was first published at 5:27 a.m. ET and was last updated at 3:48 p.m. ET.

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