WASHINGTON, D.C — Donald Trump reshuffled his campaign team again Wednesday, bringing the publisher of conservative website Breitbart into his inner circle along with a former ally of his rival Texas Sen. Ted Cruz.

The moves follow weeks of falling poll numbers and months of infighting in Trump’s campaign, as the nominee has struggled to overcome controversies that have sidetracked him from his core economic, security and immigration enforcement messages.

But the structure of Trump’s new leadership team is likely to leave the business mogul where he has long been — in charge — as those around him compete for influence. The hires also suggest Trump will continue to push an aggressive campaign against Democratic rival Hillary Clinton that dovetails closely with the most hard-hitting aspects of conservative media.

“I am committed to doing whatever it takes to win this election, and ultimately become president because our country cannot afford four more years of the failed Obama-Clinton policies which have endangered our financial and physical security,” Trump said in a statement announcing the hires.

Stephen K. Bannon will temporarily step down from his role running Breitbart News to assume the title of chief executive officer, “a new position designed to bolster the business-like approach of Mr. Trump’s campaign,” according to the statement from Trump.

Breitbart was one of Trump’s earliest and closest allies in conservative media, and editor Bannon, a former Goldman Sachs banker, is known to share Trump’s confrontational style and knack for clashing with the establishment.

A reporter and editor from the site resigned in March, citing a lack of support from Bannon after the reporter alleged that she was assaulted by Corey Lewandowski, Trump’s former campaign manager. Florida prosecutors later dropped the charge.

The statement announcing Bannon’s hire boasts that he was “once recognized by Bloomberg Politics as the ‘most dangerous political operative in America.’” Bannon produced and co-wrote a film version of the book “Clinton Cash,” which has served as a blueprint for some of the harshest attacks on Clinton. Breitbart News, whose founder, Andrew Breitbart, died in 2012, has also been credited with fueling the tea party movement and helping to drive out former Republican House Speaker John A. Boehner, exacerbating tension among warring conservative factions.

Kellyanne Conway, a veteran pollster who led super PACs for Texas Sen. Ted Cruz during the primary, will become Trump’s campaign manager. Conway led the last-gasp efforts to defeat Trump in the primaries, but later signed on as a top adviser to his campaign.

Conway will focus on communications strategy and will travel frequently with Trump while working closely with senior staff on other aspects of the campaign, Trump’s announcement said.

“I have known Steve and Kellyanne both for many years. They are extremely capable, highly qualified people who love to win and know how to win,” Trump said. “I believe we’re adding some of the best talents in politics.”

Paul Manafort, who this week faced renewed questions about his political work for a pro-Russian party in Ukraine, was effectively demoted with the hiring of Bannon, but will remain as campaign chairman and chief strategist.

Manafort had served as Trump’s de facto manager since June, after winning a power struggle that led to the ouster of Lewandowski.

But many of the problems that plagued Trump have continued since. He lags behind Clinton in fundraising and organizing, with few operators in key battleground states to help organize volunteers and churn out the vote. The campaign says it will place its first major television ads on the air this week, about two months after Clinton began airing general-election ads.

“There is a tremendous amount of organizational dysfunction in the Trump campaign that can’t be fixed by adding titles or giving people new roles,” Eric Fehrnstrom, a strategist for Mitt Romney’s presidential campaigns, said in an email. “The campaign has many problems. It lacks resources. The candidate can’t seem to stay on track. The day-to-day strategy is either misunderstood or unknown to people inside and outside the campaign.

“I don’t think those things are fixable in the short time that remains.”

Trump has also continued to make the kind of off-the-cuff comments that have distracted from his attempts to derail Clinton and broaden his support. In the aftermath of the Democratic National Convention, he spent days in a public squabble with the parents of a soldier who died in Iraq.

“The problem is not the staff; the problem has been the candidate, and the candidate’s temperament has not served him well in the general election,” said Rick Tyler, a former aide to Cruz. “This move with Bannon suggests we’re going to get more of that — and more intense, not less.”

Top Republicans have begun openly worrying about the fate of his campaign and a potential impact on congressional races.

“One the one hand, this is a silly and pointless change. The Titanic is still sinking; the water is still rising,” Rick Wilson, a veteran GOP consultant and Trump critic, said in an email. “Bannon means the Trump campaign will turn even darker.”

Trump has resisted calls from others to show more discipline in his speaking style. But on Tuesday night, he read from a teleprompter during a speech in Wisconsin, following a speech Monday in which he appeared to modify his plans to ban all Muslims from entering the country.

“I want to win,” Trump told the Wall Street Journal, which first reported the new staff hires. “That’s why I’m bringing on fantastic people who know how to win and love to win.”

Former House Speaker Newt Gingrich called Tuesday night’s speech “the clearest appeal to the African American community of any Republican nominee.”

“If he builds on this, it could be big,” he added.