Santorum, who announced he was suspending his campaign two weeks ago, had seen his once-huge lead in Pennsylvania shrink steadily and had said winning the Keystone State was key to his campaign continuing.
That said, Romney was expected to claim a huge number of delegates from Delaware, Connecticut, New York and Rhode Island, even with Santorum in the race. Nothing's happened to change that expectation, except to possibly solidify it.
While on the stump in Wilmington, Del., Romney said during a question-and-answer session President Obama was "clearly trying to hide from us what he intends to do," Delaware First Media News in Newark reported.
"He's going to hide, and it's my job to seek, and our job to seek," Romney said. "It'll be a hide and seek campaign."
Joe Aronson, executive director of the Delaware Democratic Party, and other party officials and their affiliates has been holding counter-events when Romney is in state, criticizing the former Massachusetts governor's positions on the economy among other issues.
"Romney made it clear to the middle class he doesn't care about us," Aronson told Delaware First Media, noting Romney's wealth and the 13.9 percent tax rate he paid in 2011, among other things.
But if Romney expected other candidates to bow out as well, he was mistaken because no one's conceding anything. In fact, Gingrich has picked up a few endorsements recently, including Delaware state Sen. Dave Lawson, the DailyCaller.com reported.
"The race isn't over until the votes are counted, and so I don't believe the race is over," Lawson told the 24/7 news Web site. "I believe that Speaker Gingrich certainly has a very good crack at this nomination; I believe he certainly has the right attributes to work toward putting this country back on its feet."
Lawson said if Romney becomes the nominee, he'd "absolutely" support him, but until then, the state lawmaker said he believes Gingrich is the best man.
"With his experience, his knowledge, his commonsense, his very logical approach, I think that he's something that this country needs," Lawson said. "He totally loves this country."
Delaware is the state where Tea Party-backed candidate Christine O' Donnell defeated nine-term Congressman Mike Castle, who was related to the Republican establishment, before she lost in the general election.
The Blue Hen State also is known as a state where some Republican candidates have made their last stands, and could again play such a role for Gingrich, SunshineStateNews.com, based in Tallahassee, Fla., reported recently.
Gingrich has made several visits to Delaware, which has 17 delegates.
Gingrich has won only South Carolina and Georgia and is well back of Mitt Romney in the delegate count. Yet Gingrich has insisted he'll be in the race through the convention in August.
His campaign recently unveiled a Web video with supporters discussing why they are backing Gingrich, who calls himself "the last conservative standing" in the race.
Another candidate who hasn't bowed out is Paul, who's working to galvanize a movement that favors a libertarian form of government as well as seeking a "prominent role" at the convention and ensuring voters hear his criticisms of the Federal Reserve, the deficit and the high cost of the nation's wars, Paul's campaign manager told The New York Times.
Paul's campaign has been lifted by committed young backers and it still sends supporters to local and state political conventions to try to amass delegates for the GOP national convention.
Considering the amount of time Gingrich has spent in Delaware -- especially given his financial woes -- a loss could hurt him. The state produced one Republican presidential candidate in recent decades -- former Gov. Pete du Pont in 1988, the last year Republicans carried it in a presidential election.
But local Republicans said Gingrich's push in Delaware could give him the state's 17 delegates and a crucial primary win, DelawareOnline.com in Wilmington reported.
"Delaware, being a small state, you can spend some time here and get a real bang for your buck," Delaware GOP Committeeman Laird Stabler said. "I think there's a chance he could win."
Stabler, who backs Romney, declined to speculate on why Gingrich is remaining in the race.
"I'm sure he has his reasons for continuing the campaign," he said.
Dover-area Republican state Sen. Colin Bonini, a Gingrich supporter, told DelawareOnline.com: "It's never over 'til it's over.
"He's got to keep Romney honest and it's vitally important to have a commonsense conservative voice out there," Bonini said. "I think Speaker Gingrich is going to keep the heat on."