2016 could be an apocalyptic year for the Republican Party. That’s the conclusion, at least, of pollster Stan Greenberg, who, together with Democratic strategist James Carville, operates Democracy Corps, a political consulting firm.

In “The Wave: A Guide For Progressives,” a recent report from Democracy Corps, Greenberg explains: Donald Trump’s increasingly long, threadbare coattails have endangered Republican control of the Senate, and maybe even the House of Representatives. Trump could have an impact on Republican statehouses as well.

It all depends, Greenberg says, on how Democrats characterize not just Donald Trump, but other Republicans down-ballot.

If they follow the Clinton campaign’s instruction, they will distinguish the two: your local Republican congressman is bad. But Donald Trump is dangerous.

On the other hand, Greenberg advises that in order to achieve an “electoral earthquake,” Democrats need to paint Trump as indicative of the larger problem of extremist Republican politics, which he says runs down to the local level.

“Fueling the Republican civil war and getting moderates to vote Democratic … is the biggest opportunity for progressives to play offense and produce a sustainable fracturing of the Republican Party that impacts the Congress, the states and the issues that get taken up after this electoral earthquake,” Greenberg writes.

It’s a two-front battle, in that sense, according to “The Wave.” First, tie Trump to down-ballot Republicans. Second, sell progressives on a centrist Democrat.

And yet, there are universal political answers in the year of Trump: Common sense government like infrastructure spending works, Greenberg says, and avoiding culture wars poisonous to conservatives won’t hurt, either — that would place Democrats opposite their 2012 effort, which center-staged the danger of a conservative Supreme Court challenging abortion rights.

Most of all, Greenberg writes, don’t dance around so-called “angry white working class men.” Contrary to the overwhelming beliefs of the chattering classes (and down-ballot Democratic strategists), they aren’t a monolithic group, and more important, even if they were, they’re nowhere near a large enough group to win elections on their own.

Photo: U.S. Democratic presidential nominee Hillary Clinton delivers remarks at a gathering of law enforcement leaders including New York Police Commissioner Bill Bratton (L) at John Jay College of Criminal Justice in New York, U.S., August 18, 2016.  REUTERS/Lucas Jackson