That may be part of the “Socialism!” strategy. In presidential politics, the most intensely negative campaigns have usually (though not always) been the ones that incumbents ran against challengers. The idea is to make this relatively unfamiliar person seem so terrifying that the public will stay in the familiar embrace of the incumbent. In Trump’s case, he’ll have to get Republicans as energized about turning out to vote against the Democrat as Democratic voters will be about voting against him. Anger and fear are the shortest path to that destination.
Nevertheless, Republicans may encounter some problems if “No socialism!” is the essence of their case to the public in 2020. The first is that Americans don’t generally think in ideological terms. Those of us who are immersed in politics have a clear understanding of what is meant by ideas like liberalism, conservatism and socialism, but for most Americans, it’s all kind of a vague jumble of ideas.
And because the Cold War ended 20 years ago, there isn’t the same kind of instinctive reaction when people throw the s-word around, particularly among young people. Saying “This policy is socialism” won’t be enough to turn a significant portion of the electorate against it if they weren’t already.
That's in part because Republicans have spent decades calling everything Democrats want to do "socialism," no matter how modest it was. That has convinced many voters that "socialism" just means "mainstream ideas that are more liberal than Republicans would prefer." So the word doesn't do the work they want it to.
And it isn’t even clear what someone such as McConnell means when he says the word. For instance, he has decided that the way to discredit Medicare-for-all is to refer to it as “Medicare for none.” In other words, if those socialist Democrats get a hold of health care, they’ll take away the government-provided, single-payer insurance plan you love so much.
Republicans have tried this strategy recently, without much to show for it. Holly Otterbein has an interesting look at what happened in 2018 in Pennsylvania:
In Pennsylvania last year, Republicans tagged Democrats up and down the ticket as socialists or sympathetic to socialism: Gov. Tom Wolf, congressional candidates and state representative hopefuls all got the hammer-and-sickle treatment. The strategy was deliberate and coordinated, emanating from the state’s Republican Party chairman, Val DiGiorgio.But come Election Day, Democrats flipped three House seats and 16 more in the state General Assembly. Wolf easily won reelection, as did Democratic Sen. Bob Casey.
Republicans might say, “Well, 2018 was a bad year for us all around.” And yes, it was. But crying “Socialism!” couldn’t change that. It didn’t just happen in Pennsylvania, even if it was more coordinated there; Republicans all over the country cried “Socialism!” at their opponents, and the election was still a huge win for Democrats.
We should acknowledge that there’s no telling how this strategy might work against an actual (democratic) socialist like Sen. Bernie Sanders (I-Vt.). If he wins the nomination, he’ll be biggest ideological outlier since Barry Goldwater more than half a century ago, so it’s hard to know what effect it will have when Republicans cry over and over that he’s a socialist.
But they’ve already made it clear that they’ll say the same thing about any Democrat and any Democratic policy idea, whether it’s genuinely socialist, run-of-the-mill liberal or even moderate. That’s a big reason it probably won’t work.