DON’T GET COCKY: Democrats, You May Already Have Lost the 2028 Election.

It’s early, and the contest will attract upstarts, insurgents and opportunists. Such outsiders have seized the moment in the past—sometimes successfully (Barack Obama in 2008; Donald Trump in 2016), sometimes not (Howard Dean in 2004; Bernie Sanders in 2016 and 2020). No one knows who they will be.

But they won’t be conservative Democrats. There are hardly any left. Only 8% of Democrats call themselves conservative, according to Gallup. Fifty-nine percent consider themselves liberal or very liberal. A CNN poll last summer found that one-third of Democrats and Democratic-leaning independents think of themselves as democratic socialists like Ms. Ocasio-Cortez. That share is 42% among those under 35.

Socialism’s rise raises troubling questions about the party’s future. The shift has electoral consequences. A radicalized base, animated by anti-Trump resistance, may be an asset in special and midterm elections. But open borders, social disorder and transgender ideology have hurt Democrats in presidential years. They will do so again if unchecked.

Success in 2028 thus depends on finding an appealing candidate who embodies change not only from Mr. Trump, but also from the Democrats’ reputation. That requires exactly the sort of self-examination Democrats are determined to avoid.

Bill Clinton emerged as the outsider, DLC-centrist in 1992, but only because the big names sat that one out, assuming George H.W. Bush was unbeatable following the 1991 Gulf War.

None of the big names — such as they are — seem likely to sit out 2028.

And none of those is anything like a DLC-style centrist.