Trump card - or is he a joker?

If you're an aficionado of The Apprentice, you know the punchline "you're fired" - or when it gets to the season finale and there's the final boardroom showdown, with buttock-clenchingly tense music, long cutaway shots of the final group of hopefuls left standing, waiting nervously to hear their fate - and the man in control, the capo di tutti capi, the titan of industry announces "you're hired!"

Well the person wielding all the power in the US version of the show is Donald Trump - he with an ego the size of a medium-sized planet in our solar system, a gravity-defying mop of swirling blonde hair on his head, and a bank account that could probably refloat Greece. So what would he make of a wannabe apprentice who expressed openly racist views? And not only that - a wannabe apprentice who doesn't just want any job - he wants to be leader of the free world, the president of the United States of America.

I think he would say, with barely concealed derision and scorn "you're fired". But in this case Donald Trump is the wannabe, and he wants to be hired as the Republican candidate for the US presidency.

It was at his stage-managed launch held - where else - at Trump Tower in New York that he said: "When Mexico sends its people, they're not sending their best. They're sending people that have lots of problems, and they're bringing those problems to us. They're bringing drugs. They're bringing crime. They're rapists. And some, I assume, are good people."

Immediately after those comments Republican strategists did not know whether to laugh or cry. After all, all you need do is look at the growth of the Latino population in America, assess their growing electoral importance in influencing the next presidential election, and how in the 2012 race their vote broke more or less 2:1 in favour of the Democrats, to realise that this is a group who need to be wooed and cajoled by the Republicans. But remarkably the leadership has sat on its hands, and said next to nothing. Ditto some of the other Republican candidates vying for the nomination.

I was at a breakfast this morning with one of those hopefuls, the former Pennsylvania senator, Rick Santorum, and asked him about the way Trump had expressed his views on immigration and Mexicans - all he would say is "ah well, that's Donald..."

This stands in stark contrast to the response of corporate America. There's been little hesitation there. Giants like the department store Macy's and TV company NBC Universal have cut ties. Mexican TV companies who were to screen his Miss Universe show say they want nothing to do with him. There have been protests and demonstrations, and a celebrity Latino chef who was going to open a flagship Trump restaurant in DC has quit in horror at his comments.

So why the mismatch in response? Well, the comments from Trump have struck a chord with many Republicans. In a field that contains 15 presidential hopefuls, from nowhere Trump is almost leading the pack in the polls. Someone coined the phrase after the last presidential election that the problem with the GOP was that its support was male, pale and stale - in other words, the prominent demographic was older, white men. It's beginning to look like there is a fear of offending the core, even among some of the candidates determined to widen the appeal of the party.

And so a subject that the mainstream politicians had hoped to sidestep at this election - immigration from Mexico and countries further south - is now fair and square back in the centre of political discourse.

Rival Lindsey Graham called Trump a "wrecking ball"

Of course this is a trend not unique to the USA. Look at the role Nigel Farage's UKIP played in the recent UK elections, or the Northern League in Italy, or the Front Nationale in France. If you try to ignore voter anxieties about immigration by sweeping them under the carpet, there are populist parties who will give those concerns plenty of ventilation - and win a lot of support in the process.

But Trump's appeal goes beyond any immigration concerns. Some of his supporters believe a man who has run a business so successfully can "fix" America's finances. And others no doubt like his blunt, straight-talking style.

Next month there is going to be a televised debate among the Republican hopefuls, mounted by Fox. To stop the show becoming totally unwieldy, only the top 10 candidates according to the five most recent polls will be invited to participate - Trump will be there. And far from backing down after the outcry his comments have provoked, he is amplifying them - or "doubling down" to use the American argot - and that will leave the other nine co-debaters shuffling uneasily at their podiums.

The smart money says that Trump will eventually crash and burn - a meteor that will burn super bright in the night sky, but soon to disappear in a long vapour trail.

In the meantime, somewhere in New York , a 67-year-old lady will be sitting in front of the TV, a bowl of popcorn by her side, watching Fox TV, almost splitting the seams of her pant-suit laughing.

Hillary just cannot get enough of this reality show.