Donald Trump wants to "make America great again."

"Our country is in serious trouble," Trump said when announcing his campaign for president in June. "We use to have victories, but we don't have them. When was the last time anybody saw us beating, let's say China, in a trade deal?" he asked rhetorically. "They kill us. I beat China all the time."

It's not just China that's beating the United States. According to Trump, Mexico has turned America "into a dumping ground," sending immigrants across the border who are "rapists." In response to his racially charged rhetoric, broadcaster NBC canceled Trump's Miss USA pageant. Pundits and observers thought his campaign had imploded on its launch pad.

But Trump didn't stop there. During a July interview in Iowa, he said Senator John McCain - a Vietnam veteran who was held captive and tortured - wasn't a war hero. Sacrilege in America. Outrage ensued, but Trump's campaign didn't suffer as a result.

During the first Republican debate in August, Trump refused to rule out running as a third party candidate. The audience booed him. Yet according to a Reuters/Ipsos poll published on Tuesday, Trump decisively leads the Republican primary by a 20 point margin, garnering about 30 percent support. He leads in every major primary state, from New Hampshire to Iowa, from South Carolina to Florida.

"The inflammatory comments increase his popularity," Bruce Newman, author of the forthcoming book, "The Marketing Revolution in Politics," told DW. "His brand is all about the ability to make inflammatory comments and not care about what people think."

"The xenophobic approach that Trump has, which is to appeal to people's fear of the role of immigrants, is no different than what we witness in Europe," said Newman, a professor at DePaul University. "It's no different than the oratory of a Le Pen in France."

'Not at the behest of a billionaire'

According to Newman, Trump is taking advantage of a political paradigm shift in the US. In the old days, presidential candidates had to rely on the volunteer network built by their party, in this case the Republicans. But social media has changed everything. Outsider candidates like Trump can now circumvent the party's vetters and appeal directly to the people.

"Trump is drawing tens of thousands of people because of his ability to use social media," Newman said. Some 30,000 people came out for his recent rally in Mobile, Alabama.

Trump isn't beholden to the Republican Party establishment, and he's also not beholden to wealthy donors. In 2010, the US Supreme Court upended America's campaign finance system when it allowed unlimited political spending. Money is now the lifeblood of US elections, and Trump has plenty of it.

"People look at Trump, in particular the opinion leaders, and they realize this man - who is worth 10 billion dollars (8.8 billion euros) ostensibly - is in a position to keep his campaign running indefinitely," Newman said. "He's not at the behest of a billionaire who chooses to continue or not continue to fund him and support his campaign if he's not looking that good in the polls."

Flexing muscle for white America

Bound neither by the Republican Party establishment nor its donors, Trump also is not bound by mainstream standards of decency or "political correctness." He's free to tap into populist, anti-establishment, racially charged sentiment just below the surface of American life.

Darren Davis, a professor of politics at the University of Notre Dame, believes many people are supporting Trump in reaction to Barack Obama's presidency. Many conservative white voters have watched in anger as the first African American president expanded health care coverage, negotiated with America's oldest adversaries like Iran and Cuba, criticized close allies like Israel, and issued executive orders to stop the deportation of hundreds of thousands of undocumented migrants.

"Obama is the anti-thesis of what they think America stands for," Davis told DW. "Race is a part of it, his liberal policies are a part of it, his foreign policy stances are a part of it."

Trump is speaking to the anger of these voters. He wants to end birthright citizenship, deport 11 million undocumented migrants, build a wall on the Mexican border, repeal Obama's health care reform, and take a more aggressive stance toward Islamic State and Iran.

"Trump is flexing muscle that I think white Americans would like to see in response to their reactions to Obama," Davis said. "Before race has been discussed in a very quiescent sort of way. Race has been more coated. What Trump has done is to strip racial politics of its coating."

"This type of campaigning is emotional, it appeals to people's gut reactions," he said. "It is sustainable given the lack of energy and credibility among the Republican contenders."