Donald Trump's latest anti-Muslim rhetoric is "beyond the pale" and it is time for the Republican Party to clean house, says a former member of President George W. Bush's senior staff.
Senior Republican politicians in the United States have joined the chorus of condemnation of Mr Trump after he called for Muslims to be banned from entering the country.
Rival candidate Jeb Bush called Mr Trump "unhinged", while former US Vice-President Dick Cheney said it "goes against everything we stand for and believe in".
Professor Brad Blakeman from Georgetown University, a former Republican strategist, told Nine to Noon today, Mr Trump's support was at the extreme fringes of the political spectrum.
"It's a very extreme group who claim to be Republicans. But as a Republican who has been in the party since I was 18-years-old, I don't think Donald Trump fits within the party. He is so extreme and so outrageous that he is really a Trumpeter. He's not a Republican, he is a Trumpeter.
"If you ask the vast majority of Republicans what they stand for, they stand for limited government and low taxes; and we believe in the freedom of the individual, rather than a reliance on the state, and that's basically the core values of the Republicans. Republicans do not embrace extremes.
Prof Blakeman said Mr Trump had a "slim to none" chance of winning the race for the candidacy, as extremists did not tend to win major elections in the US.
"That's why the Tea Party has not been very successful in the past few election cycles, because the people were not buying into extremist ideology. America is a just-right-of-centre nation - and in order to be elected in America, you need to be what America is. So if you're an extremist, so far in America's history you're not going to get elected."
In his latest comments, Mr Trump pledged to prevent Muslims from entering the country "until our country's representatives can figure out what is going on". His campaign manager said that would apply to "everybody".
Prof Blakeman said Mr Trump was somebody who would say and do anything he thought was necessary to win, but he had gone too far.
"As crazy as some of his statements have been, his latest statement about banning Muslims from America is beyond the pale. Enough is enough and it's really up to my party to police our own. We're ashamed of what he said. I can't imagine anybody who would believe that this is something the president of the United States should stand for and work towards. So it's really up to us to clean our own house, because in America you have to be selected by your party, before you're elected by the people."
National polls which showed Trump performing strongly did not mean very much, Prof Blakeman said.
"They are a very good comfort to Donald Trump, and have been for the first few months of his candidacy. But they are not necessarily a reflection this early of the candidate who is going to be selected by the party. The real polls that matter as we get closer to the time that we do vote are the battleground state polls. Places like Iowa, New Hampshire, South Carolina, Nevada and the Super Tuesday states that are going to come in the first part of the year. Those are the ones that really matter.
"The first test is a caucus, which is not a secret ballot, it's basically just neighbours getting together and deciding who they will support. But as soon as you get into the first secret balloting, which is the first test in New Hampshire, that's where we will really decide whether the polls were correct, or whether the polls were not, because that's when people will cast their vote, just like they would in a general election."
Prof Blakeman said he had no doubt that registered Republicans would turn away from Mr Trump when it came to that point.
"He's still there, because he's Donald Trump, and he's a reality show, and just like people slow down to see an accident this is what we're seeing. You can't turn your eyes away from it, even though you're not going to vote for him. There comes a time when the curtain comes down on entertainment, and people are actually start to think about the future of the country."