None of the inflammatory verbal bombs that businessman Donald Trump has dropped since he declared his presidential candidacy six months ago have damaged him.
Not his warning about Mexico sending illegal immigrants to the US who are "rapists" and drug dealers. Not his attack on Fox News moderator Megyn Kelly for her interrogating the reality TV star in a debate when he said she had "blood coming out of her whatever".
Not his slur – "look at that face!" – on fellow Republican Carly Fiorina. Not his character assault on another candidate Ben Carson when he likened his youthful temper to the affliction of a child molester, proclaiming: "You don't cure a child molester."
These incendiary remarks have catapulted Trump and his bombastic candidacy to the top of the polls.
They have proven his popularity as an anti-establishment candidate among white conservatives who feel disenfranchised by a political elite, blame foreigners for their economic woes and fear President Obama’s foreign policies have weakened the US and put them in jeopardy.
Trump detonated his latest bomb – and his largest – on Monday when he preyed on the fears of jittery Americans in the wake of the attacks in California, by calling for a "total and complete shutdown of Muslims entering the United States until our country's representatives can figure out what is going on".
His plan extends to stopping would-be Muslim immigrants, students, tourists and other visitors on a “temporary” basis. This is Trump’s aggressive response to the December 2nd mass shooting by a radicalised US-born Muslim man and his Pakistani immigrant wife in San Bernardino that left 14 dead.
The idea was floated on the same day a poll of Republicans in Iowa, the first state to pick the nominees in February, showed another conservative firebrand, Texas senator Ted Cruz, overtaking Trump.
The appeal of Trump's hard rhetoric was seen at a rally in South Carolina on Monday when his supporters enthusiastically responded to his plan. "I. Don't. Care," Trump told the crowd after he said some might criticise him for not being politically correct.
For the first time, his comments have united Democrats and Republicans. Before now, his own party’s responses have been tepid as Republicans fear a damaging counterattack from Trump, who despite the contempt he has shown in an angry campaign leads them by a double-digit margin in the polls.
The trouble for some of his rivals is that their policies are not far off Trump’s on that right flank and they don’t want to alienate a sizeable bloc of about a quarter of Republican voters who support him.
White House press secretary Josh Earnest said the businessman's remarks not only disqualify him from serving as president but any Republican who continues to support him.
Trump’s proposal was “morally reprehensible, counter to the constitution and has consequences for national security”, he said.
Republican speaker of the House of Representatives Paul Ryan broke his policy of not commenting on the presidential race to say that Trump's proposal "is not what this party stands for and, more importantly, it's not what this country stands for".
Even Senator Lindsey Graham, one of the more hawkish foreign-policy Republican candidates, described him as "a race-baiting, xenophobic religious bigot" and Islamic State's "man of the year".
A defiant Trump refused to back down. He was asked on ABC’s Good Morning America whether he was concerned about being compared with Hitler as Tuesday’s front page of the Philadelphia Daily News was displayed showing a photograph of the businessman with a raised hand next to the headline: “The New Furor.”
“What I’m doing is no different than FDR,” Trump said, comparing his plan to President Franklin D Roosevelt’s detention of Japanese, German and Italian immigrants during the Second World War.
Sucking up the oxygen that his radical idea has generated, Trump warned about further attacks if his plan is not followed.
"You're going to have many more World Trade Centres if you don't solve it," Trump told CNN's Chris Cuomo in a belligerent exchange.
Some commentators say Trump’s idea, which has finally drawn other Republicans off the fence, might hurt him. Others are not so sure.
"It always looks like this is a tipping point moment and certainly this might be the most outrageous claim he has made," said Julian Zelizer, professor of politics and public affairs at Princeton University.
“But given the history of the past few months we can’t say that this is going to be the beginning of the end.”
Trump’s latest bluster may be another performance in his campaign pageant and whether it is a cynical ploy or not appears not to matter.
“This is what his candidacy represents at this point,” said Zelizer. “And for many of his followers this is what they want more of.”