According to Rudge, a brusque high-school senior in Alan Bennett’s play “The History Boys,” history is “one fucking thing after another.” In the past few days, Democrats have been reminded of what Rudge meant. On Monday, the failure of a data-sharing app plunged the Iowa Democratic caucus into a state of paralysis. On Tuesday, a Gallup poll showed Donald Trump’s approval rate rising to forty-nine per cent, the highest mark of his Presidency. Later that day, Trump delivered a State of the Union address packed with falsehoods and demagoguery. On Wednesday, his impeachment trial came to an end, with the G.O.P.-controlled Senate voting to acquit, and only one Republican dissenting. Trump reacted by tweeting out a meme of his Presidency going on forever.

With nine months to go until the Presidential election, Trump’s celebratory gesture was premature, to say the least. But anyone who wants to deny him a second term needs to be clear-eyed about the challenge ahead. Most Presidents who run for reëlection win. Given his incumbency and an economy that is still growing steadily, Trump has two key advantages on his side. Defeating him is going to take a mighty effort from the Democrats and their supporters—one that combines energy, cleverness, and discipline, rather than the disorganization and dysfunction displayed in Iowa.

Since the Second World War, only three sitting Presidents have run for reëlection and been defeated: Gerald Ford, in 1976; Jimmy Carter, in 1980; and George H. W. Bush, in 1992. Nine of the twelve incumbents who sought reëlection won. In two of the three races where incumbents were defeated, the economy was—or was perceived to be—in serious trouble. With policymakers at the Federal Reserve expecting G.D.P. growth to continue at a rate of around two per cent this year, what about this November? Ray Fair, an economist at Yale, built a statistical model that seeks to forecast elections on the basis of incumbency and G.D.P. growth. Over the years, the Fair model has had a mixed record, reflecting the fact that these factors aren’t the only ones which impact elections. But the model does provide a handy way of summarizing some key factors, and it is now predicting that Trump will win the popular vote comfortably. If that happened, he would win an even bigger victory in the electoral college.

This forecast shouldn’t be taken literally. In an era of intense polarization, there is evidence that economics doesn’t play as big a role as it used to in driving voting patterns. On his Web site, Fair stresses that his model also doesn’t take into account the personality of individual candidates, which is obviously a key factor in the case of Trump. Throughout his Presidency, his job-approval rating has lagged far behind his approval rating on economic issues. That’s still true. In the aforementioned Gallup survey, sixty-three per cent of respondents said that they approved of Trump’s handling of the economy—fourteen points above his job-approval rating.

It should also be noted that the Gallup job-approval rating is an outlier. A new Reuters poll puts Trump’s rating at forty-two per cent, and an Economist/YouGov poll puts it at forty-four per cent. On Thursday afternoon, the Real Clear Politics poll average, which combines the findings from many individual surveys findings, had Trump at 45.2 per cent, with a disapproval rating of 51.8 per cent. Four months ago, his approval rating was 43.6 per cent, and his disapproval rating was 53.7 per cent. These numbers tell us that Trump is still unpopular, but that he has become a bit less so recently. Whether that shift reflects positive economic news or the impeachment trial, or both, isn’t clear.

The key point is that Trump is now sufficiently popular, and the economic environment is sufficiently benign, to make his reëlection a real and live danger. (In the online betting markets, for what they are worth, he is already a strong favorite to win.) This year, again, the result will most likely come down to ten battleground states: Arizona, Florida, Maine, Minnesota, Nevada, New Hampshire, North Carolina, and, of course, the three Rust Belt states that Trump flipped in 2016: Michigan, Pennsylvania, and Wisconsin. According to the data-research firm Morning Consult, Trump’s disapproval rating currently exceeds his approval rating in all of these states apart from Florida. But the gap has narrowed in a number of places, including Arizona, Minnesota, and Pennsylvania.

The identity of the Democratic candidate will obviously be vitally important, but so will the manner in which the campaign is conducted. Everyone associated with the Democratic Party—from grassroots activists to elected officials and Party operatives—will need to unite behind the winner of the primary, whoever it is, and avoid scoring any own goals. During a hard-fought primary election, it is difficult, if not impossible, for the various candidates and their supporters to project this sort of unity and discipline. But other Democrats are showing how it can be done.

During the impeachment trial, the House managers, and particularly Adam Schiff, laid out their arguments with such professionalism and care that even some Republican senators conceded that they had made the case persuasively. (Except in the case of Mitt Romney, of course, this wasn’t enough to persuade them to find Trump guilty.) And, after Trump’s State of the Union address, Gretchen Whitmer, the governor of Michigan, delivered a Democratic response that deserved much more attention than it got.

Rather than engaging with Trump directly, Whitmer highlighted Democratic efforts to reduce gun violence, invest in infrastructure, lower prescription-drug prices, and expand access to health care. She also contrasted these initiatives with the Trump Administration’s record of showering tax cuts on the wealthy and trying to dismantle the Affordable Care Act, including the protections it afforded people with preëxisting conditions. “It’s pretty simple,” she said. “Democrats are trying to make your health care better; Republicans in Washington are trying to take it away.”

You can argue about whether the sorts of policies that Whitmer lauded are sufficient to rebalance a society that has been so grossly distorted by political corruption, record corporate profits, and rising inequality—this debate lies at the heart of the divide between the Bernie Sanders–Elizabeth Warren and Joe Biden–Pete Buttigieg wings of the Democratic Party. In terms of campaign strategy, however, keeping the focus on everyday issues and on the mendaciousness of Trump and the Republicans offers the best prospect of defeating them in November. Despite it all, they are still beatable. Democrats need to get their act together and concentrate on the common enemy.