Donald Trump is gearing up to take advantage of a powerful new weapon in his fight against the Democrats, both now and in the 2020 election.
The President's rivals are embracing an increasingly left-wing agenda, spurred by the tranche of young progressives making waves in Congress.
When Trump attacked socialism during his State of the Union speech, many Democrats remained seated and silent. "America was founded on liberty and independence — not government coercion, domination and control," he said. "We are born free, and we will stay free. Tonight, we renew our resolve that America will never be a socialist country."
It looks set to be a major campaign issue in his battle for re-election, and Democrats are taking a big risk by leaning in to the S-word. It will force a divided United States to choose between two sides of politics that are more polarised than ever, in a dramatic reckoning over how the nation sees itself.
Republicans are gearing up for a concerted attack on the ambitious "Green New Deal" unveiled on Thursday by a group of progressive Democrats, which aims to tackle climate change and guarantee a living wage for all Americans.
The proposal — introduced by rising star Alexandria Ocasio-Cortez — aims to reduce emissions to net-zero in 10 years, provide universal health care, guarantee jobs for all with sick leave and paid holiday, and ensure retirement security.
The sweeping proposal is co-sponsored by Democratic presidential 2020 candidates Kamala Harris, Cory Booker, Kirsten Gillibrand and Elizabeth Warren, as well as possible contenders Amy Klobuchar and Bernie Sanders.
Critics including Bloomberg's Noah Smith warned that the deal included "enormous new entitlements paid for by unlimited deficit spending" — estimating it could cost $US6.6 trillion a year.
Republicans are thrilled by their opponents' shift to the left, and see it as a major boon for Trump's re-election chances, according to Axios.
GOP strategist and former White House official Andy Surabian told the website his party would argue that middle-class and low-income Americans would shoulder the burden of the plan. "The only people who can afford to be environmentalists are billionaires," he said. "Every Republican in the country should get on their hands and knees and thank Alexandria Ocasio-Cortez."
Marty Obst, senior political adviser to Vice President Mike Pence, added: "While the President and Vice President support the Venezuelan people's struggle for freedom, the Democratic Party continues its lurch toward socialism."
The Republican National Committee slammed it as a "socialist wish list" with massive costs, while GOP senator John Barrasso attacked it as a "socialist manifesto that lays out a laundry list of government giveaways".
Barrasso, chair of the Senate Environment and Public Works Committee, said the deal "would be a raw deal for American families as the cost of energy skyrockets under their leftist plan".
The proposal is set to be the linchpin for a furious battle in a Congress that only continues to move apart, despite Trump's SOTU calls for unity and bipartisanship.
Democrats hope Americans disillusioned with Trump's policies of tax cuts that benefit the rich, easing regulations on the fossil fuel industry and pulling out of the Paris agreement on climate change will be energised by the Green New Deal.
A December Wall Street Journal/NBC News national poll showed that 66 per cent of Americans believe that action is needed to address climate change, with 45 per cent calling for immediate action.
House Speaker Nancy Pelosi stopped short of endorsing the idea on Thursday, while applauding the enthusiasm of its supporters. "I'm very excited about it all, and I welcome the Green New Deal and any other proposals that people have out there," she said.
Rob Bishop, the ranking Republican member of the House Natural Resources Committee, dismissed the Green New Deal as "cute".
"When they get serious and have something that's practical, then let's talk about it," he said.
Pelosi on Thursday announced the membership of a Select Committee on the Climate Crisis, one of several Democratic bodies in the House that will prioritise climate change and environmental issues.
Democrat Sean Casten, a member of the committee, said the party should work to produce more specific proposals than the Green New Deal.
"In terms of aspirational goals, it's lovely," he said. "I'd love to live in a world that's totally clean and has green jobs for everyone and all sorts of other benefits. I don't know how you get there.
"There's a real danger in leading people off cliffs before the bridge is built."
The resolution rolled out by Ocasio-Cortez and Massachusetts Senator Ed Markey has elicited interest from the energy and technology sectors.
The proposal supports investment in "smart" power grids, climate-friendly infrastructure and zero-emission transport, along with the clean-up of hazardous-waste sites.
Height Capital Markets energy analyst Josh Price told MarketWatch the resolution was lacking detail on how it would be paid for and which technologies would be prioritised, but said investors should pay attention.
"If you start to see some more of these ground shifts in politics — veering toward renewables, veering toward addressing climate change — it's definitely bullish for these renewable energy companies and power providers," he said. "Some of those slow-money, long-time-horizon guys, the biofuels space and the renewables space are definitely interesting places to look."
He said the more "forward-looking utilities" that were shifting away from fossil fuels could be winners if there was a continued focus on limiting climate change.
The Green New Deal is likely to have the biggest impact initially in California, New York and other blue states, especially those that already have big renewable energy targets.
The nuclear energy industry was at first concerned the proposal was only focused on renewables. "We need to use every tool that works, including #nuclear, our largest source of #carbon-free energy," tweeted Nuclear Energy Institute communications adviser Matthew Wald.
But the resolution did not include a call to move away from nuclear plants, and Mr Markey said in a press conference: "The resolution is silent on any individual technology."
The deal will certainly underscore the choice between two radically different forces in US politics and the 2020 election.
Many Democrats support socialism, and according to a Gallup poll, young people aged 18 to 29 said they favoured socialism over capitalism by 51 to 45 per cent.
Republicans will make this a key part of their campaign, with White House press secretary Sarah Sanders tweeting that "Americans clearly favour the booming Trump economy over socialism that would destroy it".
Fox News host and Trump supporter Sean Hannity said: "Radical leftist Dems want more government control over your life. Is that what you want?"
But Ocasio-Cortez said the US government was already trying exercise control over American lives, even comparing her proposal to the "imagination" of Mr Trump's wall.
On both sides, she said in an NPR interview, politicians were telling voters: "Here's this hugely impossible thing that seems ridiculous, but I'm going to seriously push for it."
— with wires