WASHINGTON - Less than three months before election day, Republican presidential candidate Donald Trump is trying to reset his struggling campaign and regain momentum after a difficult period marred by controversy and sliding poll numbers.

But even as Trump attempts a reboot, he is also faced with more prominent Republican defections that threaten to undermine his effort.

Trump’s latest attempt to pivot away from his recent troubles included a renewed focus on the economy, which many voters say remains their top concern this election year.

“We are ready to show the world that America is back, bigger and better and stronger than ever before!” Trump said in a speech Monday to the Detroit Economic Club.

Economic plan

Trump outlined his plans to cut taxes, spur job growth and renegotiate trade deals; but his address was interrupted more than a dozen times by protesters, who were then escorted out of the venue.

Trump remained stoic as the protesters were removed, a departure from past rallies when he would often call for their swift removal.

A demonstrator is led away as Republican president
A demonstrator is led away as Republican presidential candidate Donald Trump delivers an economic policy speech to the Detroit Economic Club, Detroit, Aug. 8, 2016.

Trump’s speech included an attack on Democratic presidential nominee Hillary Clinton’s economic agenda, which he said would lead to higher taxes and more government regulations.

“There will be no change under Hillary Clinton, only four more years of weakness and President Obama!” he said.

Trump is hoping to turn his campaign around after a difficult week that saw Clinton surge into big leads in some national and key state polls.

Trump surrogates, such as former New York City Mayor Rudy Giuliani, tried to calm jittery Republicans on ABC’s This Week.

“I remember George (H.W.) Bush ... being 16 points down to (Democratic presidential nominee Michael) Dukakis (in 1988) going into September. So, everyone should calm down about it," Giuliani said.

Clinton in Florida

Clinton took her campaign to the key battleground state of Florida where she urged voters to be skeptical of any Trump reboot, arguing that there is “only one Donald Trump” who is by now well-known to voters.

At a rally in Kissimmee, Florida, Clinton also sought to counter what she said is Trump’s pessimistic view of the future of the country.

Democratic presidential candidate Hillary Clinton
Democratic presidential candidate Hillary Clinton takes a photo with a member of the audience after speaking at a rally at Osceola Heritage Park, in Kissimmee, Fla., Aug. 8, 2016.

?“And I am proud to be on the side of those who want to build a positive, optimistic future, who want to get the economy working for everybody and not just those on the top,” she said.

A number of experts said Trump’s best chance to alter the dynamic of the race may not come until the presidential debates, which are set to begin in late September.

“I continue to believe that this is going to come down to the first debate, which is at Hofstra University on Long Island (New York) on September 26th,” said veteran analyst Tom DeFrank of the National Journal. “I think by the end of that week we will probably know who the next president is going to be.”

DeFrank was a guest on VOA’s Issues in the News program.

Analysts and several Republican strategists also said Trump should avoid repeating some of his recent missteps that have fractured his support, like his feud with the parents of U.S. Army Captain Humayun Khan, who died in the Iraq War.

“They are the sorts of things that might turn off a small but significant part of the Republican electorate, particularly those who might be more internationally-focused and who might think that Trump just has too many rough edges to be president,” said Kyle Kondik of the University of Virginia's Center for Politics.

FILE - Republican Sen. Susan Collins speaks to rep
FILE - Republican Sen. Susan Collins speaks to reporters on Capitol Hill in Washington, June 23, 2016. Collins wrote in The Washington Post that she cannot support Republican presidential candidate Donald Trump in the fall election.

Even as Trump moves to reset his campaign, he is also dealing with more Republican defections, including Senator Susan Collins of Maine, who wrote in The Washington Post Tuesday that he is “unworthy of being our president.”

In addition, 50 former national security officials under previous Republican administrations signed a letter warning that Trump “would be the most reckless president in U.S. history.” Among those who signed the letter were former CIA director Michael Hayden and two former Homeland Security secretaries, Tom Ridge and Michael Chertoff.

Experts noted that at a time when Clinton is trying to expand her base by appealing to independents and even disenchanted Republicans, Trump still has work to do to unify his party and win over many in the Republican establishment who remain dubious about his candidacy.