Donald Trump admits he could fail in presidential bid

In a rare show of humility, Donald Trump is acknowledging his US presidential campaign faces challenges and could ultimately fall short.

Republican presidential candidate Donald Trump addresses supporters during a campaign rally. Picture: AFP/Getty

The Republican presidential nominee is straying from his signature bravado as he campaigns in the battleground state of Florida, even telling a gathering of evangelical ministers that he’s “having a tremendous problem in Utah.”

The same day, the reality show star acknowledged that his lack of political correctness could cost him the election if Americans reject his blunt approach.

“We’re having a problem,” Mr Trump told the ministers, adding that the next president could get to nominate up to five high-court justices. “It could cost us the Supreme Court.”

Trump’s campaign planned to sit down with Republican National Convention officials in Orlando on Friday. But both party officials and his campaign said the meeting was focused on Florida campaign operations and not tensions between the two.

After trouncing 16 challengers in the Republican primary, Mr Trump is encountering worrying signs as his campaign moves into the election.

Democrat Hillary Clinton’s lead over Mr Trump in national polls has widened, while a growing number of Republicans have declared they won’t support their party’s nominee.

Mr Trump’s exercise in self-awareness is a marked departure from his usual tenor on the campaign trail, where for months at rallies he would tick through poll numbers showing him winning as if they were sports scores of his favourite team.

“We’re going to win so big,” Mr Trump told a roaring crowd a month ago at the Republican National Convention. Yet on Thursday, he was reduced to citing a poll that actually showed him a few points behind Clinton and arguing the race between them was close.

Asked how he planned to reverse Clinton’s advantage, Mr Trump said he simply planned to do “the same thing I’m doing right now.”

“At the end, it’s either going to work, or I’m going to, you know, I’m going to have a very, very nice, long vacation,” Trump said.

Even while working to restore confidence in his campaign, Mr Trump appeared to court controversy anew when he said that he was open to trying Americans suspected of terrorism at the Guantanamo Bay detention centre in Cuba. “I would say they could be tried there,” he said. “That’ll be fine.”