Normally in political debate, you accuse your opponent of being wrong. Resistance implies something bigger.

To understand the candidacy of Donald Trump, start with this: Trump is the un-Obama. A lot of Americans see President Barack Obama as weak and ineffectual. They see Trump as just the opposite. The extreme opposite – not just self-assured, but arrogant.

Trump’s candidacy fits a well-established pattern in American politics.

The party out of power – the Republican Party this year – has to find out what voters want that they are not getting from the incumbent.

Obama got elected in 2008 because he was the un-Bush. President Obama is cerebral and deliberative. Not bold and reckless like George W Bush. Trump offers decisiveness, which is something a lot of voters are missing in President Obama.

Donald Trump during a campaign event at Grumman Studios in New York [Carlo Allegri/Reuters]

Trump is leading a resistance movement. Republicans are responding to Trump’s call for resistance. Resist Obamacare. Resist immigration reform. Resist trade deals. Resist Islamic radicalism. Most of all, resist the New America that came to power with Barack Obama.

A New America?

The New America is a coalition of groups that have long felt marginalised in US politics: Latinos, Asian-Americans, African Americans, Jews, working women, single mothers, gays, educated professionals, young people and the “unchurched” – the growing numbers of Americans, now more than one in five, who have no affiliation with any organised religion.

What holds the New America together is a commitment to diversity and inclusion.

Donald Trump’s resistance movement defies diversity and inclusion.

Defiance is Trump’s defining attitude. Trump defies conventional wisdom. He defies the Republican Party establishment. He defies conservative principles. He defies the press. He defies the truth.

READ MORE: Why Donald Trump draws crowds, and Hillary Clinton doesn’t

And he is not a career politician.

Many Americans are angry because government can’t solve problems any more. It can’t stop illegal immigration. It can’t keep jobs in the US. It can’t stop terrorists from killing Americans.

Trump is offering himself as a problem-solver – a leader who can get things done.

Americans believe politics is the enemy of problem-solving. And Trump can set politics aside.

“I think the voters like me, they understand me, they know I’m going to do the job,” Trump says.

Supporters cheer as Republican presidential nominee Donald Trump speaks at a campaign event in Iowa [Carlo Allegri/Reuters]

Fervent following

Trump does best among voters from the declining sectors of American life.

A study by The New York Times found that Trump’s strongest support is in places with high percentages of whites with no high school diploma, low numbers of ethnic and religious minorities, “old economy” jobs such as in agriculture and manufacturing, and low labour force participation rates – Appalachia, for instance.

What you find in those places are Americans who have been left out of the economic recovery, whose jobs are threatened by foreign trade, who are declining demographically and whose traditional religious and cultural values are under challenge.

They believe they are now the ones being marginalised.

They’re an angry resistance movement, and Trump is their leader. They hate liberals such as President Obama with their snobbish condescension. And they hate conservatives such as Mitt Romney with their heedless rapacity.

Trump has a fervent following, some of whom persist in believing his bizarre assertions.

He started his political ascent as the leading proponent of the “birther” theory – the idea that President Barack Obama is not a natural-born US citizen and is therefore an illegitimate president. That idea has been conclusively disproved. But it continues to thrive on the political fringe.

A supporter of Republican presidential nominee Donald Trump attends a campaign rally in Nevada [Reuters]

When Trump attacked Muslim Gold Star parents who had lost a son fighting for the US, Trump claimed in a tweet, “The story is not about Mr Khan [the father] … but rather RADICAL ISLAMIC TERRORISM.”

He charged that President Obama was a “founder” of ISIS and Hillary Clinton a “co-founder”.

Trump has said, “We are led by a man that either is not tough, not smart, or has something else in mind.”

Something else in mind? Trump insinuates that “there’s something going on” and leaves it to his supporters to imagine what it could be.

Normally in political debate, you accuse your opponent of being wrong. Resistance implies something bigger.

It implies that your opponent is not just wrong but illegitimate – a fraud, a cheat, a usurper, a criminal.

Trump calls for Hillary Clinton to be sent to jail.

If he loses, don’t expect Trump to fade away.

There is talk of his starting Trump TV. That will give him a platform to keep the resistance alive and agitate opposition to everything President Clinton wants.

At the end of the campaign, a Trump enthusiast told a rally in Las Vegas that their mantra has to be “Attack, attack, attack! We will never accept defeat! We will never give up!”