Leftists and moderates, stop fighting. You need one another.

In 2004, I went to Ohio to cover John Kerry's campaign to unseat George W. Bush. For liberals, the race felt existential. The Bush administration had lied America into war in Iraq, where an entirely predictable insurgency was raging. His military and CIA were torturing people; the Abu Ghraib scandal had broken open in April.

A worshipful cult of personality surrounded the president, whose administration was nakedly disdainful of truth. Yet four years earlier Bush had lost the popular vote, in a race in which progressives were divided and a decisive number voted third party. Surely, it seemed, with the right mobilization, Democrats should be able to defeat him this time.

Liberal groups launched what Matt Bai described in the New York Times Magazine as "the largest get-out-the-vote effort ever undertaken to win a single presidential campaign." It wasn't enough. Democrats did increase their turnout, but Republicans increased theirs even more.

Reporting from Ohio megachurches and right-wing rallies, I could see that many conservatives were motivated by the specter of same-sex marriage, which had been recognized in Massachusetts a few months earlier. In the election, 11 states including Ohio — including Oregon — passed ballot initiatives against same-sex marriage. Postelection surveys showed that "moral values" beat out issues like Iraq and the economy as voters' chief concern.

As I look back from 2020, two things seem obvious to me. LGBTQ activists had justice on their side, even if the campaign for marriage equality caused a terrifying backlash before it triumphed. At the same time, it's understandable why Democratic politicians like Barack Obama publicly opposed same-sex marriage in 2008, because to do otherwise risked producing permanent right-wing rule. Good policy and good politics are not the same thing.

The 2004 election illuminates some of the dilemmas faced by today's Democrats, who are locked in an internecine battle between progressives and moderates. It's a frustrating and destructive fight because both sides are partly right.

It's the job of the activist left to push political limits, staking out positions that sound radical today but could, with enough work, seem like common sense in the future. But in the short term, an assertive left that garners national attention can threaten the political survival of Democrats who answer to a more conservative electorate.

But most candidates who endorsed those initiatives were in safer districts than those who didn't. When moderate Democrats like Conor Lamb and Abigail Spanberger say that left-wing slogans are poisonous in their communities, people who don't live in those communities should take them seriously.

Left-wing populists often believe that there's a silent majority who agree with them, if only they can be organized to go to the polls. If that were true, though, an election with record high turnout should have been much better for progressives. Instead, 2020 was a reminder of something most older liberals long ago had to come to terms with: The voters who live in the places that determine political control in this country tend to be more conservative than we are.

Yet that doesn't mean that the Democratic Party doesn't need the left. Leaders like Bernie Sanders and Ocasio-Cortez were loyal soldiers in this election. After the primaries, they put aside their disappointment to rally voters whom Joe Biden might not have reached. One analysis showed that voting by young people was up 8% in 2020, and after the coronavirus, the issues young Biden voters cared about most were racism and climate change. The Democratic Party can't afford to alienate the people inspired by Sanders and the Squad.

The Democrats' loss in 2004 was devastating, but recovering from it didn't mean moving right. At the time, even civil unions for gay couples were controversial — the Ohio ballot initiative was one of several that banned them along with same-sex marriage. Agitation for marriage equality turned support for such unions into the moderate liberal position, then into the centrist position. Then marriage equality became the law of the land.

Similarly, the Green New Deal made a climate plan like Biden's, the most ambitious ever proposed by a major party presidential nominee, look moderate. Calls to defund the police are unpopular, but the slogan has already made other reforms — like changing the law to make it easier to hold police officers liable for misconduct — seem centrist and practical.