Donald Trump says he’s unbeatable if Republican party backs him

Donald Trump has called for Republicans to rally behind his presidential candidacy.

He has cruised to primary victories in three more states.

He said that he could not be defeated in the November election if he was the standard-bearer of a united party.

On the Democrat side, Vermont senator, Bernie Sanders, handed former secretary of state, Hillary Clinton, a surprise loss in the industrial state of Michigan, increasing the likelihood that the contest for the party’s nomination could stretch into early summer.

Clinton, however, crushed Mr Sanders in the southern state of Mississippi, continuing to win a large margin among black voters.

Speaking to MSNBC, Trump said: “If the Republican party unites behind us, nobody can beat us.”

But Trump evaded questions about how he would actualise his campaign promises, especially his boast that he would build a wall along the Mexican border to stop illegal immigration, and make Mexico pay for it.

He did concede that he was not doing as well with women voters, because of the stinging language of his campaign.

“I can see women not necessarily liking the tone (of his campaign), but I had to be very harsh to win,” he said of his brutal counter-attacks on party elites and fellow candidates, particularly Florida senator, Marco Rubio, and Texas senator, Ted Cruz.

Trump’s lead over Cruz grew by only 15 delegates. That is because all four states awarded delegates proportionally, so even the second-place finisher got some. Cruz captured the Idaho primary, in the west of the country.

Mr Rubio, the favourite of the party establishment, failed to pick up any delegates on Tuesday.

He needs to win his home state, Florida, next week, while Ohio governor, John Kasich, needs to win his home state, on Tuesday, to stay in the race.

Among Republicans, Trump has at least 446 delegates and Cruz has at least 347. Rubio has at least 151 delegates, and Kasich has at least 54.

It takes 1,237 delegates to win the party nomination.

While Sanders upset Clinton in Michigan, she increased her delegate lead by sweeping Mississippi, and is now halfway to the number needed to clinch the nomination.

After Tuesday’s results, Clinton has accumulated 1,221 delegates and Mr Sanders 571, including superdelegates, the party insiders who can support whomever they like.

Democrats need 2,383 delegates to win the nomination.

Sanders said that “in almost all national polls” he was the bigger winner against Mr Trump. Clinton focused on Republicans and the election.

“We are better than what we are being offered by the Republicans,” she declared.

The economy ranked high on the list of concerns for voters in Michigan and Mississippi.

At least eight in 10 in each party’s primary said they were worried about where the American economy was heading, according to exit polls conducted by Edison Research, for The Associated Press and television networks.

Among Democrats, eight in 10 voters in both states said the country’s economic system benefitted the wealthy, not all Americans.

Sanders has sought to tap into that concern, energising young people and white, blue-collar voters, with his calls for breaking up Wall Street banks and making tuition free at public colleges and universities.

But Sanders has struggled to win the support of black voters, who are crucial to Democrats in the general election.