Trump has beaten analysts' predictions again and again. While six months ago, no one expected him to clinch the nomination, that scenario looks increasingly possible now. And while just a couple of months ago analysts thought he could never beat likely Democratic nominee Hillary Clinton in the general election, now analysts say he can.

The brash businessman has appealed to a widespread sentiment in the United States that the country is going in the wrong direction, and has capitalized on the country's anti-Washington sentiment.

Trump supporters believe the last several years of the administration of US President Barack Obama have been a disaster both economically and in terms of foreign policy.

They believe not only the Democratic White House but also the Republican-led Congress has failed them, and see Trump as a successful businessman who has created thousands of jobs while career politicians in Washington have never started a business or created a job in their entire careers.

Critics say Trump is selling snake oil, and contend that his policies are unworkable and even ridiculous. They also take umbrage with Trump statements viewed as anti-immigrant and anti-Muslim.