If you talk to the most passionate advocates for any Democratic presidential contender, they’ll tell you that their candidate will not just beat Donald Trump in the presidential election, he or she will destroy him. They each have their own theory about exactly why this will happen — Joe Biden will win working-class whites, Sen. Bernie Sanders (I-Vt.) will energize young people, etc. — but they’re convinced that their candidate is the only one who doesn’t represent a huge risk of Trump winning reelection.

But it’s not too early to accept a fact about the general election, one that will not change no matter who the Democratic nominee is: Not only will this election be extremely close, it’s going to be nearly impossible to tell what will happen until Election Day.

That’s because the real uncertainty lies in this question: Who is the electorate actually going to be? We won’t know until they show up, or don’t, at the polls.

Let’s take a look at the latest Washington Post/ABC News poll, which tested general election matchups:

This image might be a little misleading because it makes small differences look large, so let’s consider the numbers. Trump trails Biden by 4 percentage points, Sanders by 2, Mike Bloomberg by 3 and Sen. Amy Klobuchar (D-Minn.) by 1. He is tied with Sen. Elizabeth Warren (D-Mass.) and leads former South Bend, Ind., mayor Pete Buttigieg by 3. That grouping is tight enough — all within the margin of error — that it doesn’t tell us anything about who actually has a better chance against Trump.

Nor should it. We have no idea yet what will happen during the general election — perhaps most important, what tsunami of attacks Trump and the Republicans will unleash on the Democratic nominee and how that nominee will react to them. Right now voters are basing their judgments on very sketchy and incomplete information about the Democrats.

But they know how they feel about Trump, and that’s where the really important numbers in this poll are. Against every Democrat, Trump gets almost the same support: 46 to 48 percent. That’s what he has when matched up against a man or a woman, a socialist or a moderate, a millennial or a septuagenarian. Even against the one candidate he leads in this poll, Buttigieg, he still gets 48 percent. And unless there’s some truly cataclysmic event like a swift and severe recession, that’s where he’s going to stay all the way to Election Day.

It also happens to be just what he got in 2016. Trump received 46 percent of the popular vote, and if you eliminate third parties and just count the two-party vote, he got 49 percent. Hillary Clinton’s 2-point advantage over him was about what the polls said she’d win; unfortunately, her steady lead convinced just about everyone that she was sure to be the next president, when his votes happened to be distributed more advantageously for the electoral college.

None of us should be surprised if the polls from now until November show pretty much the same thing: Trump at around 46 to 48 percent and the Democrat with a slight lead. It may bounce around a bit from week to week, but that will probably be the broad picture.

Which brings us back to the question of who the electorate is. Both the Trump campaign and Democratic candidates like Sanders and Warren hope their campaigns could change the composition of that electorate. Trump will try to do it in two directions: He’ll seek to turn out working-class whites who are irregular voters but got to the polls for him four years ago, and he will almost certainly repeat the efforts he undertook in 2016 to suppress the votes of blacks and other minority groups. Those efforts will be aided by state Republican parties that have waged a relentless voter suppression campaign through the use of voter purges, voter ID laws, rollbacks of early voting and the selective closure of polling places in Democratic areas.

The more liberal Democrats believe they can expand the electorate by organizing and motivating young voters, single women, minorities and anyone else inclined to vote Democratic but who doesn’t always vote. Moderates like Biden and Klobuchar might pay some lip service to that idea, but their core strategy is to accept the composition of the electorate pretty much as it is but hope to convert some Trump voters and win a higher proportion of the small population of independents.

While polling can circle around questions of the electorate’s composition by asking people things like how certain they are to vote or whether they know where their polling place is, it’s extremely difficult to do with precision, not least because people routinely lie to pollsters to make themselves seem civically engaged. We just won’t know whether the efforts the parties have undertaken will work until Election Day.

And we certainly can’t know today. Which means that every day from now to November will be filled with anxiety and dread. Just like the rest of the Trump era.

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