Despite the recent return of Democratic optimism associated with the Harris-Walz ticket, there are a few stubborn fears that keep partisans awake at night. Here’s a review of four of them that I wrote at New York:

Democrats are in a vastly better state of mind today than they were a couple of months ago, when Joe Biden was their presidential candidate and his advocates were spending half their time trying to convince voters they were wrong about the economy and the other half reminding people about how bad life was under President Trump. While it’s possible this would have worked in the end when swing voters and disgruntled Democrats alike took a long look at Trump 2.0, confidence in Biden’s success in November was low.

Now that the Biden-Harris ticket has morphed into Harris-Walz, there’s all sorts of evidence from polls, donor accounts, and the ranks of volunteers that Democrats can indeed win the 2024 election. But at the same time, as Barack Obama and others warned during the Democratic National Convention, the idea that Kamala Harris can simply float on a wave of joy and memes to victory is misguided. She did not get much, if any, polling bounce from a successful convention, and there are abundant signs the Harris-Trump contest is settling into a genuine nail-biter.

While the September 10 debate and other campaign events could change the trajectory of the race, it’s more likely to remain a toss-up to the bitter end. And many fear, for various reasons, that in this scenario, Trump is likelier to prevail. Here’s a look at which of these concerns are legitimate, and which we can chalk up to superstition and the long tradition of Democratic defeatism.

Republicans’ perceived Electoral College advantage

One reason a lot of Democrats favor abolition of the Electoral College is their belief that the system inherently favors a GOP that has a lock on overrepresented rural states. That certainly seemed to be the case in the two 21st-century elections in which Republicans won the presidency while losing the national popular vote (George W. Bush in 2000 and Donald Trump in 2016). And in 2020, Joe Biden won the popular vote by a robust 4.5 percent but barely scraped by in the Electoral College (a shift of just 44,000 votes in three states could have produced a tie in electoral votes).

However, any bias in the Electoral College is the product not of some national tilt, but of a landscape in which the very closest states are more Republican or Democratic than the country as a whole. In 2000, 2016, and 2020, that helped Republicans, but as recently as 2012 there was a distinct Electoral College bias favoring Democrats.

To make a very long story short, there will probably again be an Electoral College bias favoring Trump; one bit of evidence is that Harris is leading in the national polling averages, but is in a dead heat in the seven battleground states that will decide the election. However, it’s entirely unclear how large it will be. In any event, it helps explain why Democrats won’t feel the least bit comfortable with anything less than a solid national polling advantage for Harris going into the home stretch, and why staring at state polls may be a good idea.

Recent polling errors

For reasons that remain a subject of great controversy, pollsters underestimated Donald Trump’s support in both 2016 and in 2020. But the two elections should not be conflated. In 2016, national polls actually came reasonably close to reflecting Hillary Clinton’s national popular-vote advantage over Trump (in the final RealClearPolitics polling averages, Clinton led by 3.2 percent; she actually won by 2.1 percent). But far less abundant 2016 state polling missed Trump’s wafer-thin upset wins in Michigan, Pennsylvania, and Wisconsin, largely due to an under-sampling of white non-college-educated voters. The legend of massive 2016 polling error is probably based on how many highly confident forecasts of a Clinton win were published, which is a different animal altogether.

There’s no question, however, that both national and state polling were off in 2020, which is why the narrow Biden win surprised so many people. Two very different explanations for the 2020 polling error have been batted around: One is that the COVID pandemic skewed polling significantly, with Democrats more likely to be self-isolated at home and responding to pollsters; the other is that the supposed anti-Trump bias of 2020 polls simply intensified. The fact that polls in the 2018 and 2022 midterm elections were quite accurate is consistent with either interpretation.

So we really don’t know if polling error is a given in 2024, or which candidate will do better than expected. A FiveThirtyEight analysis of polling error since 1998 shows a very small overestimation of the Democratic vote across 12 election cycles. It might be prudent, then, to expect that Trump might exceed his polling numbers by a bit, but not necessarily by a lot.

Fundamentals in election forecasts

A lot of election forecasts (or model-based projections) incorporate, to varying degrees, what are known as “fundamentals,” i.e., objective factors that are highly correlated historically with particular outcomes. There are models circulating in political-science circles that project presidential-election results based mostly or even entirely on macroeconomic indicators like GDP or unemployment rates. Others take into account presidential approval ratings, the positive or negative implications of incumbency, or historical patterns.

While forecasts vary in how to combine “fundamentals” with polling data, most include them to some extent, and for the most part in 2024 these factors have favored Trump. Obviously the substitution of Harris for Biden has called into question some of these dynamics — particularly those based on Biden’s status as an unpopular incumbent at a time of great unhappiness with the economy — but they still affect perceptions of how late-deciding voters will “break” in November.

The high chances of a chaotic overtime

A final source of wracked Democratic nerves is the very real possibility — even a likelihood — that if defeated, Trump will again reject and seek to overturn the results. Indeed, some MAGA folk seem determined to interfere with vote-counting on and beyond Election Night in a manner that may make it difficult to know who won in the first place. Having a plan B that extends into an election overtime is a unique advantage for Trump; for all his endless talk about Democrats “rigging” and “stealing” elections, you don’t hear Harris or her supporters talking about refusing to acknowledge state-certified results (or indeed, large batches of ballots) as illegitimate. It’s yet another reason Democrats won’t be satisfied with anything other than a very big Harris lead in national and battleground-state polls as November 5 grows nigh.