“There is great anger” – that was Donald Trump’s pitch to the nation as he portrayed himself as the ultimate outsider, the only one able to clean up the “swamp” in Washington.

Four years later we are back for another election campaign and the anger has only deepened, the swamp is only muddier.

Those expecting Trump to have learned the act of civility and statecraft during his years in office are likely to be disappointed. During 2015 and 2016 the president perfected a tone that left no room for politeness. He will always tell it “how it is”, even if that means deceptions, vagaries and outright falsehoods.

From when the would-be president descended the escalator at Trump Tower in 2015 to begin his campaign by condemning Mexican “rapists”, the die was cast. Outrageous statements meant air time and column inches – it also brought the added bonus of supporters. Trump has been hooked ever since.

The president sees no difference as we head to 2020, hence his tweets attacking Democrat representatives Alexandria Ocasio-Cortez of New York, Ilhan Omar from Minnesota, Michigan’s Rashida Tlaib and Ayanna Pressley from Massachusetts – all of whom are seen as easy targets. Trump has attacked women before, constantly saying his 2016 rival should be “locked up” and saying of Republican candidate Carly Fiorina “Look at that face! Would anyone vote for that?”

The Democrat challengers to Trump in 2020 Show all 25 1 /25 The Democrat challengers to Trump in 2020 The Democrat challengers to Trump in 2020 Bernie Sanders The Vermont senator has launched a second bid for president after losing out to Hilary Clinton in the 2016 Democratic primaries. He is running on a similar platform of democratic socialist reform Getty The Democrat challengers to Trump in 2020 Joe Biden The former vice president recently faced scrutiny for inappropriate touching of women, but was thought to deal with the criticism well and has since maintained a front runner status in national polling EPA The Democrat challengers to Trump in 2020 Elizabeth Warren The Massachusetts senator is a progressive Democrat, and a major supporter of regulating Wall Street Reuters The Democrat challengers to Trump in 2020 Amy Klobuchar Klobuchar is a Minnesota senator who earned praise for her contribution to the Brett Kavanaugh hearings Getty The Democrat challengers to Trump in 2020 Michael Bloomberg Michael Bloomberg, a late addition to the 2020 race, announced his candidacy after months of speculation in November. He has launched a massive ad-buying campaign and issued an apology for the controversial "stop and frisk" programme that adversely impacted minority communities in New York City when he was mayor Getty Images The Democrat challengers to Trump in 2020 Tulsi Gabbard The Hawaii congresswoman announced her candidacy in January, but has faced tough questions on her past comments on LGBT+ rights and her stance on Syrian President Bashar al-Assad Getty The Democrat challengers to Trump in 2020 DROPPED OUT: Pete Buttigieg The centrist Indiana mayor and war veteran would be the first openly LGBT+ president in American history Getty The Democrat challengers to Trump in 2020 DROPPED OUT: Deval Patrick The former Massachusetts governor launched a late 2020 candidacy and received very little reception. With just a few short months until the first voters flock to the polls, the former governor is running as a centrist and believes he can unite the party's various voting blocs AFP/Getty The Democrat challengers to Trump in 2020 DROPPED OUT: Beto O'Rourke The former Texas congressman formally launched his bid for the presidency in March. He ran on a progressive platform, stating that the US is driven by "gross differences in opportunity and outcome" AP The Democrat challengers to Trump in 2020 DROPPED OUT: Kamala Harris The former California attorney general was introduced to the national stage during Jeff Sessions’ testimony. She has endorsed Medicare-for-all and proposed a major tax-credit for the middle class AFP/Getty The Democrat challengers to Trump in 2020 DROPPED OUT: Bill De Blasio The New York mayor announced his bid on 16 May 2019. He emerged in 2013 as a leading voice in the left wing of his party but struggled to build a national profile and has suffered a number of political setbacks in his time as mayor AFP/Getty The Democrat challengers to Trump in 2020 DROPPED OUT: Steve Bullock The Montana governor announced his bid on 14 May. He stated "We need to defeat Donald Trump in 2020 and defeat the corrupt system that lets campaign money drown out the people's voice, so we can finally make good on the promise of a fair shot for everyone." He also highlighted the fact that he won the governor's seat in a red [Republican] state Reuters The Democrat challengers to Trump in 2020 DROPPED OUT: Cory Booker The New Jersey Senator has focused on restoring kindness and civility in American politics throughout his campaign, though he has failed to secure the same level of support and fundraising as several other senators running for the White House in 2020 Getty The Democrat challengers to Trump in 2020 DROPPED OUT: Wayne Messam Mayor of the city of Miramar in the Miami metropolitan area, Wayne Messam said he intended to run on a progressive platform against the "broken" federal government. He favours gun regulations and was a signatory to a letter from some 400 mayors condemning President Trump's withdrawal from the Paris Climate Accord Vice News The Democrat challengers to Trump in 2020 DROPPED OUT: Kirsten Gillibrand The New York Senator formally announced her presidential bid in January, saying that “healthcare should be a right, not a privilege” Getty The Democrat challengers to Trump in 2020 DROPPED OUT: John Delaney The Maryland congressman was the first to launch his bid for presidency, making the announcement in 2017 AP The Democrat challengers to Trump in 2020 DROPPED OUT: Andrew Yang The entrepreneur announced his presidential candidacy by pledging that he would introduce a universal basic income of $1,000 a month to every American over the age of 18 Getty The Democrat challengers to Trump in 2020 DROPPED OUT: Julian Castro The former San Antonio mayor announced his candidacy in January and said that his running has a “special meaning” for the Latino community in the US Getty The Democrat challengers to Trump in 2020 DROPPED OUT: Marianne Williamson The author and spiritual adviser has announced her intention to run for president. She had previously run for congress as an independent in 2014 but was unsuccessful Getty The Democrat challengers to Trump in 2020 DROPPED OUT: Eric Swalwell One of the younger candidates, Swalwell has served on multiple committees in the House of Representatives. He intended to make gun control central to his campaign but dropped out after his team said it was clear there was no path to victory Getty The Democrat challengers to Trump in 2020 DROPPED OUT: Seth Moulton A Massachusetts congressman, Moulton is a former US soldier who is best known for trying to stop Nancy Pelosi from becoming speaker of the house. He dropped out of the race after not polling well in key states Getty The Democrat challengers to Trump in 2020 DROPPED OUT: Jay Inslee Inslee has been governor of Washington since 2013. His bid was centred around climate change AFP/Getty The Democrat challengers to Trump in 2020 DROPPED OUT: John Hickenlooper The former governor of Colorado aimed to sell himself as an effective leader who was open to compromise, but failed to make a splash on the national stage Getty The Democrat challengers to Trump in 2020 DROPPED OUT: Tim Ryan Ohio representative Tim Ryan ran on a campaign that hinged on his working class roots, though his messaging did not appear to resonate with voters Getty The Democrat challengers to Trump in 2020 DROPPED OUT: Tom Steyer Democratic presidential hopeful billionaire and philanthropist Tom Steyer is a longtime Democratic donor AFP/Getty

“I think his rhetoric shows a fundamental approach to demagogic politics that underlay Trump’s 2016 campaign and has been a constant since,” said Joshua Geltzer, a former national security official in the Barack Obama administration and executive director of the institute for constitutional advocacy and protection at Georgetown University. The four congresswomen are all critics of Trump’s policies on immigration and he knows that attacking them and looking strong on border control will play well with his base.

His aim, Geltzer said, is to solidify his support. Trump is not aiming for moderates. If the president can ensure they come out in strong numbers in November 2020, there is a decent chance he stays in the White House.

The language of telling the four women – despite not mentioning the progressives in his tweet – to “go back” to the countries they came from is not just insulting but plays into the insidious nature of Trump’s rhetoric.

Of the quartet, only Omar – who is originally from Somalia – was not born in the United States, but she was made a US-citizen in her teens. Suggesting otherwise is playing into the white nationalist rhetoric that some supporters of the president love.

While the White House has always said that Trump condemns the white supremacists and neo-Nazis that have flocked to his cause in recent years, these statements are a dog-whistle to them. Indeed, it makes the argument around whether Trump is racist that pops up every time such comments appear seemingly increasingly academic.

From late 2015, when Trump called for a “total and complete shutdown of Muslims entering the US” – with Omar a Muslim – to saying there was violence on “both sides” following a white nationalist rally in Charlottesville, there is a thread that can be followed through Trump’s political life.

Geltzer believes that Trump knows the reaction his tweets will bring, and cares little. Hence his comments from the White House on Monday saying that if the four congresswomen were “not happy in the US ... you can leave”.

“Trump clearly feels that incendiary rhetoric is the way to grab headlines and promote himself,” Geltzer said. “He seems if anything emboldened on using racist and misogynistic language designed to spark outrage but also rally certain constituencies”.

Clinton’s campaign spokesperson Glen Caplin said after one Trump rally in 2016 that the now-president uttered a “a litany of nutty conspiracy theories, hypocritical attacks and over a dozen outright lies debunked by fact checkers”. In the three years since, the criticism has changed little.

Immigrant and veteran congressman Ted Lieu calls Donald Trump 'racist ass' live on air

One thing that has changed is the grip that Trump now has on the Republican Party. In 2015, establishment figures in the GOP were lining up to call him foolish – including many of his rivals and 2012 presidential candidate Mitt Romney.

Once Trump become the nominee the attacks died down, with many conservatives now seeking to just swallow the president’s steamrolling of office norms as long as he continues to fill court benches with conservative judges and back anti-abortion positions. Eight years of Trump in the White House will mean little if the make-up of the courts has been altered for decades longer.

The clearest example of this is Republican senator Lindsey Graham of South Carolina, who was calling Trump a “kook” and a bigot three years ago, but now joins him for golf games and praises his intelligence – a key acolyte who now has the president’s ear. Power and clout can bring any number of changes.

It was likely not an accident that Mr Trump quoted Graham in one of his collection of tweets defending himself on Monday – saying that policies of the progressive Democrats will “destroy our country”.

The host of MSNBC’s Morning Joe programme, Joe Scarborough, was quick to condemn the relative silence from Republicans on Monday morning.

“I’m going to be looking today at Mitt Romney [now a Utah senator], Ben Sasse [a Nebraska senator], other Republicans who in the past who have had the courage to speak out,” he said. “These are not the words of an American president we heard over the weekend. These are the words of David Duke, Klans members and white nationalists; neo-Nazis. They know it. They know it. They need to condemn it today.”

Later on Monday, Republican Pennsylvania senator Pat Toomey said that Trump was “wrong” and that the four congresswomen’s citizenship is as “valid as mine”. He added that while he disagrees with the group on most policies “we should defeat their ideas on the merits, not on the basis of ancestry”.

The Democrat-led House of Representatives is also expected to hold a vote ”condemning the president’s xenophobic tweets”.

Trump will use any stick to beat Democrats and his aim will have been to try and keep driving a wedge between the four Democrat women he attacked and Democrat house speaker Nancy Pelosi with his latest tweets. Pelosi represents the establishment and the four progressives have been sure to stand up to her on policy. Ocasio-Cortez also questioned why Pelosi was telling women of colour to back off when the house leader was challenged, with Trump taking that to mean she was calling Pelosi racist.

All four congresswomen hit out at Trump’s “racism” in condemning them and Pelosi said that the president’s plan to Make America Great Again has always been about “making America white again”.

But even this will play into Trump’s persecution gambit. Despite being an integral part of the establishment now, the president will always try and show his supporters he is an outsider.

Support free-thinking journalism and attend Independent events

Attacks on progressive or leadership Democrats will do that, as will hitting out at poll numbers and media stories. And it is likely to only get worse, according to Geltzer.

“With Trump, the question is how to stay in the headlines,” he said. “And if he feels that garnering headlines means upping the ante for his already-vicious rhetoric, then so be it – he’ll do so, and we will hear even worse things from him today than we did in 2016.”