Newt Gingrich, who once led the Republican presidential field only to see his standing diminished after a string of losses, will reduce his campaign schedule and lay off a third of his staff in a strategy shift that underscores his fading chances of claiming the party’s nomination.

The former House speaker has already replaced his top aide, Michael Krull, with Vince Haley, who had been deputy campaign manager and a policy adviser. Gingrich, who had pinned his hopes on a strong showing in the South but won only his home state of Georgia and neighboring South Carolina, will continue to visit primary states but will begin a post-primary strategy that zeroes in on the Republican National Convention, his aides said.

“Our campaign is focused on winning a big choice convention this August in Tampa and is making necessary adjustments to leadership and personnel to execute our strategy,” said Joe DeSantis, Gingrich’s communications director.

The changes were first reported by Politico.

The shake-up comes as Republicans are increasingly coalescing around Mitt Romney, who leads the delegate race by what seems to be an insurmountable margin.

Gingrich, who found little support for his candidacy among the party establishment, faced calls to drop out of the race after a poor showing in Alabama and Mississippi, but has long declared that he will stay in all the way to the convention.

It is likely to be a rocky path as Gingrich faces a string of contests in big moderate states, where he has struggled to gain footing and his campaign is struggling to raise money.

The campaign reported $1.6 million in debt at the end of February and $1.5 million in cash, according to filings.

At the end of 2011 and in January,Gingrich had more money in the bank than he had debt, but in the most recent report he was in the red overall. “The money’s very tight, obviously,” he said at an appearance in Maryland on Tuesday. “We have the money to keep going.”

For much of the race, Gingrich has run a live-off-the-land style campaign that involved soaring debate performances and the type of provocative sound bites in the free media that have become his trademark.

In a race where voters have demanded anger and passion from their candidates, Gingrich has often fit the bill, slamming the media, his fellow Republicans and President Obama with harsh but memorable language.

After winning the South Carolina primary in January, Gingrich’s campaign faltered badly, and he struggled to find a consistent message since, veering from angry populist to champion of a moon colony.

Aides said that going forward, he will run a positive, Internet-driven and idea-focused race, a familiar pledge from a campaign that has often been short on strategy but long on the bold pronouncement.

As polls showed him leading the Republican field, Gingrich flatly declared just a few months ago that he was very likely to be his party’s nominee, but he has struggled against Romney’s superior ground game, infrastructure and money.

Although he was able to make a strong comeback after much of his staff quit last summer, his campaign never capitalized on the momentum coming out of his South Carolina victory.

In the delegate count, Gingrich trails badly, and he has gained few delegates in the most recent contests because of such a poor showing. His scaled-back primary schedule comes as Rick Santorum tries to close a yawning delegate gap with Romney and narrow the race to a two-man contest, even as the former Massachusetts governor racks up endorsements and seems to be on his way to becoming the nominee.

But Gingrich suggested Tuesday the race could still have another twist.

“If we get to June 26 and Governor Romney does not have a majority, I think you’ll then have one of the most interesting open conventions in American history,” he said.

Staff writers Chris Cillizza, Greg Masters and Amy Gardner contributed to this report.