The rhetoric is familiar: the demands to take the country back. The railing against an out-of-touch elite. The anger at a rigged economic system.

But now the insurgent cries that propelled Donald Trump to the White House have been taken up by stunned opponents as they try to galvanise anger and fear over his election into a strategy to resist his policies and remake the left as a credible political alternative.

“People came out on the streets because they were in shock,” said Gregory McKelvey, an experienced activist who founded a protest group, Portland’s Resistance, as thousands joined spontaneous demonstrations in the liberal west coast city within hours of Trump’s victory. “Now we are seeing a rising up of people to say it’s supposed to be our country. The government’s supposed to fear us, not the other way around.

“The majority of Americans feel like it’s time for a big change and Donald Trump is pushing for one form of drastic change. We are pushing for another.”

The tide of protests that swept US cities was matched by a wave of individual acts of resistance. Some rallied on the streets and online under the banner Not My President. Facebook groups popped up to plan how to challenge Trump over climate change and misogyny. Donations to civil liberties groups surged in defence of Muslims, immigrants and freedom of speech.

An online petition demanding delegates to the electoral college switch their support to Hillary Clinton because she won the popular vote has received more than 4m signatures. Activists in California and Oregon began the legal process for their states to declare independence from the US, albeit an unlikely prospect.

But as shock and protest gave way to more considered strategies, the focus shifted from the twin issues of opposition to the more egregious of Trump’s proposed policies and how to build a liberal political movement more representative of working Americans, with or without the Democratic party.

Social justice organisations supporting immigrant rights, fighting for the environment or tackling institutional racism have been abruptly forced to shift their attention from long-term policy to defence of existing rights in the face of Trump’s threat of mass deportations, climate change denial and attacks on Black Lives Matter.

The environmental group 350.org called Trump’s election “a disaster” and said: “The climate movement will put everything on the line to protect the progress we’ve made.”

Latino organisations are laying plans to shield young undocumented immigrants who benefitted from an Obama presidential executive order protecting them from deportation. Trump can abolish it with the stroke of a pen.

Some cities have promised to remain places of “sanctuary” for undocumented immigrants. In Portland, the public schools board passed a resolution limiting immigration officials’ access to campuses. The city’s schools superintendent warned of a rise in racism tied to Trump: “We have seen a number of incidents of hate speech over the last several months, and it has risen significantly since (the election).”

In other parts of a state sharply divided between liberal cities and strongly Republican rural areas, groups opposing discrimination say there has been a sharp increase in attacks on minorities.

Other activists are focused on how to exploit what they see as the inevitable failure of Trump’s economic policies when they do not deliver the jobs and prosperity he has promised.

“What you’re seeing with this current reaction to Trump is it’s going to expand, especially as Trump [puts in place] his economic plans which will be terrible for all these people,” said Kevin Zeese, a lawyer and co-director of the Washington DC-based Popular Resistance, a movement bringing together groups from Occupy to Veterans for Peace. “You’re going to see him funnel money to the top, trillions of dollars to the top, and most people’s lives getting worse. You’re going to see healthcare go out of control. People who voted for him on economic issues are going to realise they were bamboozled by a salesman.”

Clinton’s defeat has re-energised Sanders backers who say the election proved the socialist contender was right to focus on economic injustice. Photograph: A Jones/PacifiC/Barcroft Images

Zeese said Trump would be exposed as no more than a front for corporate interests and that would only fuel opposition. He said the example for popular resistance to the new president’s policies was the widespread popular opposition to the Trans-Pacific Partnership trade deal. Obama pushed it hard but communities blaming lost jobs and industries on other trade deals, such as the North American Free Trade Agreement which moved factories to Mexico, resisted.

“This is a victory of mass movement. That’s what won. The people defeated transnational corporate power. The most powerful corporations in the world and they lost,” he said. “It is a model for what the movement should be doing next.”

One of the most divisive questions among progressive activists is where the Democratic party now fits into the opposition to Trump. There is wide acceptance that Clinton lost because she was a poor candidate, too closely tied to corporate interests and who failed to connect with large numbers of voters who see the economy as working against them. Above all, she was a candidate of continuity in an age demanding change.

Adam Green, co-founder of the Progressive Change Campaign Committee who worked for the Democratic National Committee on John Kerry’s 2004 presidential campaign, said Clinton issued a flurry of policy papers on important economic issues that failed to address the central issue of a rigged economy and had little resonance with voters.

“The Democrats need to be willing to say that our economy is rigged against the little guy, our democracy is corrupted by big money and we will fight Trump’s pro-corporate agenda and dedicate ourselves to fixing this rigged system,” he said.

McKelvey was a delegate for Bernie Sanders to the Democratic convention. He reluctantly cast his ballot for Clinton in the general election.

“I voted for Hilary Clinton out of fear. I was worried that this was an election of change and an election where we don’t know what’s going to happen and it’s possible that Donald Trump could even win,” he said.

Like other Sanders supporters, McKelvey was resigned to Clinton’s victory and deeply unenthusiastic about the prospect of her presidency. But Clinton’s defeat re-energised Sanders backers who say the election proved the socialist contender was right to focus on economic injustice and the corruption of American politics by big corporations, and that the Democratic party needed to embrace that.

McKelvey takes it as a good sign that Sanders, who is an independent, not a Democrat, and Elizabeth Warren have been given leadership roles by the party in the Senate. The leading contender for chair of the Democratic National Committee, a despised organisation among Sanders supporters because it worked in favour of Clinton’s nomination, is Keith Ellison, the first Muslim elected to Congress and widely regarded as one of the more authentic voices in the party.

The New York Times reported that Democrats in Congress were trying to forge a policy agenda that exploits Trump’s divisions with his own party on issues from trade agreements to increased infrastructure spending and maternity benefits.

That’s a strategy that will be eyed warily by some opponents of Trump, who say that he will get the credit for policies that succeed and Democrats will be blamed if they don’t.

“The real question is, do Democrats stand up with backbone for longtime progressive principles or do they treat Donald Trump like a normal president, which he’s not, and compromise their principles?” said Green.

Others have proposed following the Tea Party’s example and running more progressive candidates for Congress in Democratic primaries which, even if they do not win, might have the effect of shaping policy.

Zeese is not confident the party will change its ways.

“The Democratic party has to choose between the Wall Street big donor interests and their voters. They conflict,” he said. “They have to put forward economic policies that show they’ve really listened, that they got the message from this election. We get it. It’s the economy, stupid, and it’s not working for most Americans.”

Zeese said the party was not helped in its efforts to win back support by what was perceived in parts of the US as prosperous liberals smearing economically struggling voters for their support of Trump.

“If you look at the states that essentially decided the election – Michigan, Ohio, Wisconsin, Pennsylvania and Indiana – they’re all states that have voted for Obama in the past. These are not racist voters. They voted for the first African American president. They did so because of economic issues,” he said. “We need to unite around issues. Identity politics gets in the way of that. Democrats make a mistake playing that card. It means a lots of white working class [people] whose interests are not being represented. There are legitimate issues around race and injustice, women and injustice, but they have to be put into the context of an economy that doesn’t work for most people in United States.”