WASHINGTON • In previous attempts to explain the racist, xenophobic bile that periodically spews forth from Mr Donald Trump's mouth, pundits have been partial to an explanation that combines brashness and egotism.

The businessman, now a leading contender for the Republican nomination for United States President, speaks so loosely and is too proud to apologise that, so the thinking goes, he ends up always having to double down on crazy things he did not always mean to say in the first place.

After his latest outrage - a preposterous proposal to ban Muslims from entering the US - even that barely plausible excuse has to be tossed out the window.

This time, Mr Trump was not caught by a "gotcha" question from a reporter, nor was he responding to a proposal put forward by someone else. The idea, instead, came in an unsolicited press statement and was later defended by his proxies.

"Donald J. Trump is 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," stated the press statement, leaving no ambiguity as to what the presidential candidate's intentions are.

But as outrageous as the statement was, Mr Trump's stance and the mix of reactions that followed do capture the current mood in America.

Despite the outpouring of condemnation that greeted his proposal, it will shock no one if the presidential hopeful's polling numbers suffer no ill effects.

In the wake of last month's terror attacks in Paris and the mass shooting in California by a self-radicalised couple, American society is once again divided, with some going so far as to say that the anti-Muslim sentiment now is even worse than it was in the weeks after the Sept 11, 2001 attacks in New York and other cities.

The fact that Mr Trump's comments did not meet universal condemnation attests to that assessment. As disheartening as it was to hear one man - albeit an influential one - put forward such a proposal, the sight of a room of Americans giving him a standing ovation for it was worse.

Even as the leadership of his own party was denouncing his remarks, thousands of supporters in South Carolina gave the candidate resounding applause the moment he uttered his Muslim ban.

It is not just the Trump fans who are on board.

Texas Senator Ted Cruz, a Republican presidential candidate who is targeting the same support base as Mr Trump, refused to denounce his opponent.

While he said he disagreed with the plan, he actually praised Mr Trump: "I commend Donald Trump for standing up and focusing America's attention on the need to secure our borders."

Former senator Rick Santorum, another Republican candidate, similarly stopped short of criticising Mr Trump, putting forward instead an only slightly less offensive version of the ban.

"I've proposed actual concrete things and immigration law that would have - not the effect of banning all Muslims, but a lot of them..., " he said in an interview on a conservative radio show.

Mr Trump and hare-brained proposals aside, Muslim groups are reporting unprecedented levels of anti-Muslim sentiment in the wake of recent terror attacks.

The Council on American-Islamic Relations, the largest Muslim advocacy organisation in the US, said that it received more reports about acts of Islamophobic discrimination, intimidations, threats and violence targeting American Muslims and Islamic institutions in the week-and-a-half since the Paris attacks "than during any other limited period of time since the 9/11 terror attacks".

In one of the most extreme cases, a group of "protesters" turned up outside a mosque in Irving, Texas, armed with loaded rifles and carrying anti-Islam signs.

It was the second time this year Irving made headlines for the wrong reasons.

The world was introduced to the town in September when 14-year-old student Ahmed Mohamed was arrested because a teacher thought his homemade clock looked like a bomb.

Poll numbers also provide evidence that politicians such as Mr Trump have a receptive audience for their brand of extremism.

A YouGov poll of 1,000 people conducted earlier this year found that 55 per cent of those surveyed had an "unfavourable" opinion of Islam. Tellingly, the majority of all respondents did not work with anyone Muslim or had Muslim friends.

And with Muslims forming anywhere between 1 and 2 per cent of the population, the candidates can rest easy knowing that even a complete loss of the Muslim vote would not make a significant difference to their chances.

DIVISIVE POWER OF AN ELECTION CAMPAIGN

That the Islamophobia problem seems bigger now than it was after the Sept 11, 2001 attacks can be put down to timing.

Though 9/11 remains the worst terror attack on American soil, it took place in what was otherwise a relatively stable environment.

The US faced relatively few geopolitical challenges abroad and then President George W. Bush - barely a year into his first term - was years away from the pressures of another election.

All that enabled him to set a careful tone. Mr Bush may not have been able to stop the anti-Muslim prejudice but, by promptly and pointedly refusing to blame Muslims, he limited the poisonous xenophobic and anti-Muslim invective in post 9/11 politics.

As Mr Nathan Lean, director of research for the Pluralism, Diversity and Islamophobia project at Georgetown University, said: "Thanks in large part to the patient language of President Bush at that time, those within the Republican Party who might have otherwise expressed or acted upon antipathy towards Muslims were not given the licence to do so. Today, there is no such leadership in the Republican Party, and the result has been that candidates such as Mr Donald Trump and Dr Ben Carson take advantage of real anxieties, and cater charged messages to pockets of people who then feel emboldened and, in some cases, act out against the Muslim community."

To make matters worse, the inflammatory statements are drowning out the adult voices. Just a day before Mr Trump's wild proposal, President Barack Obama made a televised address where he urged Americans not to discriminate against Muslims. By Wednesday, all anyone could talk about was Mr Trump's Muslim ban.

TOO LITTLE, TOO LATE

The presidential campaign is certainly not the only factor explaining the wave of Islamophobic comments. It is simply amplifying and catalysing existing tensions that have been simmering beneath the surface all this while.

The 14 years since 9/11 have provided no evidence that American society is somehow better prepared to deal socially with the fallout of terrorist attacks. This may be due to everyone focusing too much on only one part of the problem.

The investment and training in law enforcement, emergency preparedness and intelligence gathering have been second to none, but there does not seem to have been similar interest in trying to build a more inclusive society - one where people do not so quickly regard one another with suspicion.

While Muslim groups continue to push back against extremism, they have for a long time operated without much attention or support. Only last year did the White House begin a pilot project to counter violent extremism, to largely mixed results. The project - started in Boston, Los Angeles and Minneapolis-St Paul - laid out a series of programmes to identify and counter self-radicalisation.

However, its overtly narrow focus on Muslim communities has led critics to say that the programme feeds the narrative that one religious group is somehow more responsible than others. Still, it remains the tentative first steps in roughly the right direction.

The US' struggles do provide some worthwhile lessons for countries everywhere that are no doubt grappling with parallel issues.

The speed at which this country reverted to its post-9/11 state of anxiety and mistrust demonstrates clearly the fragility of social harmony.

The other noteworthy point is the difficulty of trying to fix a social problem after it is fully manifested.

Last week, just days before the shootings in San Bernardino, Singapore's Deputy Prime Minister Tharman Shanmugaratnam was invited to give a speech in the US capital about housing policy and building an inclusive society.

One point he made during his address was that governments no longer had the choice of whether to engage in social policy.

The choice was either to do it upstream or tackle the consequences downstream - either design policy to mitigate social forces from the get-go or be forced to react to any negative outcomes that emerge. His comments can be seen in a new light, given the tragic events that took place subsequently.

US leaders this week are learning that exhortations to stay united have little effect when negative social forces have been allowed to act unfettered.

For Singaporeans, continuous harping about building resilience in society has made the issue something of a cliche, but seeing trust unravel this quickly in a community subjected to duress provides a vivid reminder of what can happen if the work is neglected.