It seems like only yesterday conservatives were concluding that after a long battle, the culture wars have been lost, overwhelmed by campuses and corporations imposing as the new American normal a preoccupation with identity, race and gender. No one ever put this imposition to a vote, but so what? Wars are about winning, not your opinion.

Four years ago, Hillary Clinton made the tactical error of identifying the culture war’s losers as “deplorables,” and enough of them stirred to hoist Donald Trump into the presidency.

This election wasn’t going to be about the culture. Just over three months ago, it was about one thing—“Trump.” Democrats wanted to make the president alone the main voting issue, and that’s the focus Mr. Trump himself prefers.

Then a hurricane happened May 25 on a Minneapolis street. In its aftermath, the election, incredibly, is now about “Portland.”

“Portland” has become a proxy for nearly 100 days of nationwide street marches, riots, smashed historical monuments, fires, lootings, shootings, the rise of Black Lives Matter, and embattled cops in multiple cities enduring a hail of rocks and industrial-grade fireworks. As the guy in Queens said, what happened?

Mr. Trump has blasted Portland, Ore., Mayor Ted Wheeler as “a fool,” “do-nothing” and “wacky.” Instead, he should make Mr. Wheeler honorary co-chairman of the Trump re-election campaign.

Long faded are daily mainstream-media obsessions over Russia collusion, the Mueller investigation, Adam Schiff’s hearings and impeachment. The coronavirus pandemic alone would have been enough for voters to sort out, but the list of 2020 voting issues now includes civil order and whether the police protect or impede it, the meaning of “crime,” novel interpretations of America’s founding history, patriotism, free speech as a right versus cancel culture as a social necessity, even the Second Amendment right to bear arms, as when your life’s business is being torched.

Joe Biden and most Democrats wouldn’t have chosen this course, but the left loves the culture war, so it’s back. Americans are normally slow to alter political loyalties, but what has tipped the scales is the daily display of incompetent progressive governance.

In just three months, public officials in city after city have shown themselves incapable of executing the minimal responsibilities of government. Some don’t even seem interested, as with Mayor Wheeler or New York City’s Bill de Blasio.

Until this, the left existed in some minds as being about banning fossil fuels or conservative speakers on campus. Yawn. Bernie Sanders’s socialism could once be minimized as a hard-to-achieve economic reorganization. Today, the ruin of great swaths of American cities is real, justified daily by the Democratic left as a social revolution the U.S. needs right now amidst battling Covid.

The Trump campaign saw the political implications in these events and created an impressive convention about getting back to basics, with substantive, well-written speeches by everyday people, including black Americans dissenting from the Democrats’ now-conventional wisdom of Black Lives Matter. The left canceled Francis Scott Key, so the Republicans did Star-Spangled-Banner patriotism.

Before this, the culture war had been effectively lost because the left, with the support of America’s opinion-forming platforms, got acquiescence for their views from so many major institutions. Still, there is no bigger institution than the American city, and the Democratic left has let civilized life itself degrade. Nor is there much evidence it sees limits on disorder as a political tool.

Because of these disturbing events and the ideas attached to them, it appears that some anti-Trump independents, suburbanites and centrist Democrats are reconsidering where their own interests lie. The race is tightening.

Let us not overstate the Democratic disadvantage. Donald Trump has Ted Wheeler. But Joe Biden has Donald Trump.

Rather than let Mr. Biden and the Democrats struggle inside the ideological trap they set for themselves, Mr. Trump is now threatening to do to the protests what he did in the coronavirus’s early days—insist he is the story and overhype anything he does.

Even as some shift occurs in his direction, the president also seems fascinated in public by the war’s marginal battlefields, such as QAnon (“I understand they like me very much”) or his assertion in a Fox interview that Mr. Biden is controlled “by people that are in the dark shadows.”

Mr. Trump’s instinct for sarcasm-strewn bludgeoning of his opposition may cause gettable voters to conclude the Democrats’ original strategy was right, that this election really is about voting against Donald Trump.

The electorate still up for grabs has two months to decide which war is more unsettling—the one in the streets or the one inside Mr. Trump himself?