After picking up an honorary degree from a Scottish university, the American property tycoon told journalists his country needs better leadership and he might run against President Obama.
"A lot of people have asked me to do it and until recently I would have no interest," he said.
Trump said Obama was "having a very hard time."
"I think he would be the first to admit that things have not been easy for him. The US is a great country and it's not doing as well as it should. It could be doing much better and I think, with proper leadership, it would do unbelievably well," Trump said.
He said it was too early to say who his potential running mate would be, and laughed off suggestions that he might run with former Alaska Gov. Sarah Palin.
Trump received an honorary doctorate in business from Robert Gordon University in Aberdeen, despite protests from local residents who claim his massive 750 million pound ($1.2 billion) golf resort development could force them out of their homes.
Some academics from the university joined the campaign against Trump, arguing that the tycoon doesn't deserve the degree. But the university counters that students have much to learn from his business savvy.
Trump, resplendent in his academic robes, complained about a lack of demonstrators: "I heard there was going to be a big protest and nobody showed up."
Local homeowners claim Trump wants to force them out to make room for his luxury resort, which features a five-star hotel, more than 1,000 homes and two golf courses. It is expected to open in the summer of 2012.
David Kennedy, a former head of the university, said that Trump ignored the local planning committee to build the golf resort near the residential Menie Estate north of Aberdeen.
"That is not the work of an honorable businessman," Kennedy said. "The university should be bestowing honorary degrees to people who are honorable, respected for their contribution to society and most importantly a role model for the students. Donald Trump is none of these."
Tripping Up Trump, the protest group opposing the development, collected an online petition with 6,500 signatures against the honorary degree in four days. Local resident Susan Munro presented the petition to the university on Wednesday.
"If I had one thing to say to Mr. Trump it would be 'Go home,'" said the 57-year-old. "As for Robert Gordon University, it is all about the money, they are just after Mr. Trump's money."
Trump walked the back nine holes of the golf course on Wednesday and said the first players would tee off in June or July 2012.
Ian Wood, the chancellor of Robert Gordon University, hailed the tycoon's "visionary world-class golf investment," which he said would "put Scotland on the world golfing map."