The improbable candidate has become the de facto nominee.
Businessman Donald Trump effectively sealed the Republican Party nomination for the US presidency with a win in Indiana on Tuesday that forced his closest rival, Senator Ted Cruz, out of the race.
Even some Republican party leaders who had plotted to stop Mr Trump's insurgent push admitted the tycoon was now the party's presumptive nominee. Mr Trump beat Mr Cruz 53 per cent to 37 per cent in a state that many had considered a do-or-die contest for the senator.
Mr Cruz had tried every trick in the book to try and win the state. He even made the unprecedented move of picking a vice-presidential running mate and formed an awkward alliance with Mr John Kasich, who was reported by NBC News to have decided to suspend his campaign.
On the night of one of his biggest victories, Mr Trump scaled back his trademark bombast, praised his Republican colleagues and called for party unity. "We have to bring unity. It is so much easier if we have it," he said. "We're going after Hillary Clinton. She will not be a great president, she will not be a good president, she will be a poor president. She doesn't understand trade…"
Mr Trump's unlikely triumph - he is the first outsider to secure nomination - leaves Republicans in a bind whether to continue to distance themselves or rally behind him.
And while the Republican nominating contest has wrapped up early, the Democratic Party is carrying on. In Indiana, Senator Bernie Sanders bounced back from a string of defeats to secure a narrow upset victory over former secretary of state Hillary Clinton. He still has little chance of overhauling her lead but has vowed to stay in the race till the end.
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