By Samuel P. Jacobs
WASHINGTON (Reuters) - Newt Gingrich's wild ride of a presidential campaign could soon be coming to an end.
The Republican candidate is reassessing his candidacy after rival Mitt Romney easily won Delaware, one of five northeastern states holding presidential primaries on Tuesday, and the state where Gingrich campaigned most heavily.
"I think we need to take a deep look at what we are doing," Gingrich told NBC in an interview on Monday.
Republican front-runner Romney delivered a speech billed by his campaign as his first address of the general election campaign against Democratic President Barack Obama.
Romney won all 17 delegates up for grabs in Delaware and 56 percent of the vote, almost 30 points ahead of Gingrich, results showed with almost all votes counted.
Despite a string of losses since his upset victory in South Carolina's primary in January, Gingrich had vowed to stay in the race until his party's nominating convention in late August.
His withdrawal would clear the way for Romney to claim the unofficial mantle of the Republican nominee in November's election, putting to rest a bitter primary campaign.
Tuesday's primaries in Connecticut, Delaware, New York, Pennsylvania, and Rhode Island were the first since the departure of former U.S. Senator Rick Santorum, who was running second to Romney in the state-by-state nomination battle.
The weak showing for Gingrich, a former speaker of the U.S. House of Representatives, was another blow to the candidate who fell behind Santorum as both vied to be the conservative alternative to Romney.
THINKING ABOUT STAYING IN RACE?
Current and former advisers to the Gingrich campaign paint a picture of a candidate who wants to stay in the campaign and, despite much evidence to the contrary, sees a path forward.
A strong finish in Delaware, they said, would have given Gingrich a reason to stay in the race until North Carolina votes, along with two other states, on May 8.
His campaign released a detailed schedule of events, taking Gingrich and his wife, Callista, to museums, a zoo and several receptions in North Carolina this week.
A former staffer also said Gingrich even filmed a victory video to be released after Tuesday's primaries, suggesting that he was thinking about staying in the race.
Even so, "there's going to be a conversation among the team over the course of the next few days," said Charlie Gerow, a Pennsylvania strategist and Gingrich supporter.
Advisers said Romney's claim to the nomination is premature.
"There really is an inability of Romney to make the final sale," said former U.S. congressman Bob Walker, a Gingrich supporter.
The former staffer, a past state director for Gingrich, said the pace at Gingrich's Virginia headquarters has slowed. Where 50 staffers once worked, now a dozen appear, many leaving their desks at 5 p.m. each day — a rarity in a profession known for its long work days.
But, the former state director said, Gingrich can seem oblivious to his situation.
OUT OF LIMELIGHT, INTO DEBT
More than any other presidential candidate, Gingrich has felt the impact of independent "Super PACs," the political action committees that have no limits on how much money they can raise or spend in support of candidates.
Throughout the primary season, Gingrich has depended on the largesse of a PAC called Winning Our Future, which received at least $21.5 million in donations from billionaire casino mogul Sheldon Adelson and his family.
At the same time, a pro-Romney PAC, Restore Our Future, spent $19 million on ads attacking Gingrich.
The former speaker's campaign has not recovered from that assault, and has been unable to keep raising enough money to cover its expenses. Last week's campaign finance filings with the Federal Election Commission showed $4.3 million in debt.
Gingrich's money crunch was clear when he started renting out his email list to advertisers this month.
The onetime front-runner has been largely out of the media glare for weeks. His biggest headline came after an encounter with a biting penguin at the St. Louis Zoo left him with a bandaged finger.
Gingrich, who rose to be the most powerful Republican in the United States during his leadership of the House in the 1990s, has finished first in just two of the 31 states that have voted in the 2012 presidential contests.
His candidacy, if now short on promise, has never lacked drama. In June, his top campaign staffers abandoned ship, jumping aboard Texas Governor Rick Perry's campaign after what they saw as an ill-advised cruise Gingrich took to the Greek islands, with Callista, his third wife, who became a permanent presence on the campaign trail.
Campaigning to return Washington's fiscal house to order, Gingrich was criticized for his sizable lines of credit at Tiffany's, the luxury jeweler.
Now viewed as a sideshow, Gingrich's campaign was once at center ring. In December, polls showed Gingrich soaring ahead of Romney, but after a barrage of ads from Restore Our Future that cast Gingrich as a Washington insider with questionable ethics, he plummeted to finish fourth in the Iowa caucuses on January 3.
Then Gingrich pulled off a shocking win in South Carolina, a critical primary, only to see more negative advertising halt his momentum in Florida.
Gingrich's hope for the nomination dimmed further when rival Republican candidates declined requests to attend future debates in March. A pugnacious presence, Gingrich excited followers with his bravura performances and slashing attacks on the media during the televised events.
"Ron Paul, Rick Santorum, and Mitt Romney decided we are not going to get on stage with him anymore," said Katon Dawson, a South Carolina operative who left Gingrich's campaign to advise Perry. "Once he lost that platform, he lost the ability to ignite his campaign."
(Editing by David Lindsey and Christopher Wilson)