Socialism.

It’s the buzzword that’s become the Republicans’ go-to attack on Democrats thus far in the 2020 campaign. The mere mention of it drew some of the loudest boos of the night at President Trump’s campaign rally in Manchester, N.H., Thursday.

“A vote for any Democrat in 2020 is a vote for the rise of radical socialism and the destruction — the destruction of the American dream,” Trump said, the line nearly drowned out by a chorus of disapproval that reverberated through the SNHU Arena.

The general election is still 443 days away, but Democratic presidential hopefuls are already keenly aware of the effect the label could have on their prospects. During the July debates, Mayor Pete Buttigieg of South Bend, Ind., said, “If we embrace a far-left agenda, they’re going to say we’re a bunch of crazy socialists. If we embrace a conservative agenda, you know what they’re going to do? They’re going to say we’re a bunch of crazy socialists.”

Strategists and political watchers say it’s a page out of the incumbent playbook — one that could have legs depending on who becomes the Democratic nominee.

“Republicans are calculating that they have to make a case between the devil you know and the one that you don’t,” said University of New Hampshire political science professor Dante Scala. “So one of the ways to do that is for Trump and the Republicans to say, well, you may not like me, but you won’t really like the alternative. By trying to affix the socialist tag to Democrats, that’s one way to try to do that.”

Trump went that route in Manchester, turning his boasts of a strong national economy and low unemployment in the Granite State into a jab at neighboring U.S. Sen. Elizabeth Warren of Massachusetts, saying, “We have the best numbers we’ve ever had — let’s vote for somebody else? I don’t think that’s going to happen.”

Republican strategist Patrick Griffin said the socialist label “is going to cost the Democrats the election.”

“The problem for Democrats is that they’ve defined that the way to deal with Trump is to behave so radically that they are unelectable after the primary. Bernie Sanders, Elizabeth Warren — and you can go right down the line — are so marginalized by the fact the Democratic Party has been pushed so far down the left they can never be right,” Griffin said.

While Warren and Sanders, the Vermont U.S. senator and self-proclaimed democratic socialist, could be pigeonholed by the tag, political watchers say socialism is far less applicable to the current front-runner, former Vice President Joe Biden, and several lower-polling but more moderate candidates.

“If Bernie’s the nominee, than that will have legs,” said Democratic strategist Neil Oxman. “If Biden’s the nominee — no one’s going to stick Joe Biden with being a socialist.”

The effectiveness of the socialism label could also depend on the state of the economy by Election Day. As Trump travels the country promoting his economic policies, fears of a recession swirl with each erratic day on the stock market.

Democratic operative Patrick Dorton said as it stands, though, “The U.S. has created 50% more jobs than Europe and Japan combined since the 1980s. A European socialist model that has been pushed by Bernie and sometimes Warren is certain to turn voters off in a general election, even Democratic voters.”

The portrayal of Democrats as socialists seemed to resonate with some of Trump’s base at his rally Thursday.

Joann Hanson, a nurse and Nashua, N.H., independent, said she wants people “to have their own choice” when it comes to health and “not be a socialist country” with policies like “Medicare for All.”

But strategists say it’s unclear whether it’ll win over the general electorate. Trump remains underwater in polls in the Granite State — with 53% disapproval and 42% approval in the latest UNH survey. A Fox News poll released Thursday shows Trump trailing Biden, Sanders, Warren and California U.S. Sen. Kamala Harris in head-to-head matchups.

Scala said if undecided New Hampshire voters are “convinced that the alternative to Trump would be big, structural change” — echoing Warren’s campaign stump — “that might not be a comfortable fit.”

Democratic strategist Tony Cignoli said a socialist or socialist-leaning nominee could “scare off many more middle-road, independent and unenrolled voters,” and could affect outcomes in swing states like Michigan, Ohio and Pennsylvania.