As the Democratic candidates Hillary Clinton and Bernie Sanders continue to battle it out for delegates, Mr Trump will now turn his full attention to undermining Mrs Clinton, who he sees as his main opposition on the path to the White House. In what was once an unthinkable scenario, the billionaire property magnate may yet become president of the United States of America.
Famous also for his role on television in The Apprentice, Mr Trump has carried an air of invincibility about him for several months. His closest rival, Ted Cruz, was forced out of the race yesterday and Mr Cruz's supporters, along with those in the far Right of the Republican Party, must be wondering where it all went wrong.
The trouble for the Republicans started several elections ago when the Super Pacs, the anonymous fundraising entities set up by wealthy backers of the party, started selecting the candidates they wanted rather than the candidates who moderates felt they could vote for in an election.
Those funds are known to pour millions upon millions of dollars in to support candidates they believe mirror their own belief of lower taxes, very flexible labour laws and the right to remain wealthy. Inequality is used as an election tool.
President Barack Obama challenged that belief, becoming the first African-American president. His healthcare changes were vehemently opposed by the Super Pacs and Republicans made gains in mid-term elections on the back of the money poured into their campaigns if they opposed healthcare reforms for the poor.
As Mr Obama broke the mould, so does Mr Trump. He basically funded his own election campaign, although campaign donors - reading the winds of polling - started their contributions.
Mr Trump was opposed by the Republican Party which challenged him along the way to pull out of the race, even threatening a contested nomination and the possibility of dropping in a ‘‘moderate'' to steal the nomination from him at the last minute. All that failed.
But what do we know about Mr Trump, whose campaign so far has been one of derision, personal attacks and bluster? For one, he is a fan of Russian President Vladimir Putin. But Mr Trump also believes Nato nations should be paying more of their fair share when it comes to keeping the peace in global conflicts.
Russia has caused its share of those conflicts in recent years. Mr Trump's policy on China remains volatile but he accused the world's second-largest economy of ‘‘raping America''. That comment gained him a large following of people who find their jobs threatened by free-trade proposals and the flood of cheaper imports into the US.
In an interesting comment after Mr Trump's win yesterday, a supporter said: ‘‘It's nice to have a politician who says what he thinks rather than what is always politically correct'', adding Mr Trump would not be the first president to be rude and crude.
With Mrs Clinton seen as an establishment candidate, and Mr Sanders pursuing a contested nomination, Mr Trump has a free run to the election on November 8. In contrast, Mrs Clinton still needs to get the required number of delegates to secure the nomination earlier than the Democratic convention in late July.
Mr Trump is just as likely to tear the Republican Party apart. Beholden to no-one, he can quite literally make up his own rules on campaigning and it will be a foolish party administration to stand in his way.
The evolution of American politics will advance rapidly this year with either the first woman elected as president; or the election of the least politically experienced candidate in recent history.
