If Donald Trump manages to win the general election in November, historians of the future may trace the start of his march to victory to May 13, 2016. That was the day the Obama administration announced that all public schools in the country would have to provide transgendered students access to the bathroom of their choice or face a loss of federal funds (and possible Justice Department lawsuits under Title IX).

But how could this be, when Trump's position on this and other culture-war issues is wishy-washy at best?

Because in recent years elections have been increasingly fought and won in negative terms, with most people voting in favor of one party not so much because they love it as because they despise the other side. This is likely to be truer than ever this year, with two colossally unpopular candidates lining up against each other. Most Clinton voters will be casting ballots against Trump, and most Trump voters will be casting ballots against Clinton — and President Obama's decision to become a champion of transgender rights just might be enough to move a significant number of culturally conservative voters who have been troubled by Trump firmly into the anti-Democrat column.

Why did Obama do it? The answer isn't especially clear to me because I'm not the right kind of liberal.

In purely political terms, the decision seems inexplicable. The number of transgendered people in the United States is vanishingly small — something on the order of 0.3 percent of the population. Many people, like me, who have no problem with allowing transgendered adults to use the bathroom of their choice nonetheless think it misguided to indulge the decisions of children in this area. (Kids aren't allowed to drink alcohol, drive, vote, work, or volunteer to fight in the military, but they should be permitted to change their birth gender?)

Then there's the fact that in 2016, with both political parties contending with populist insurgencies, the stakes in this battle seem almost comically low. (We can all agree that, as President Obama put it, the "dignity" of transgendered children is important. Whether ensuring the legal recognition of that dignity is something that should concern the president of the United States is another matter.)

But by far the most important reason why the president would have been wise to remain silent on the issue is that before the administration went out of its way to kick the hornet’s nest, those who oppose allowing the transgendered to use the bathroom of their choice were on track to lose the fight. Within hours of North Carolina passing a new law strengthening restrictions on the use of public restrooms, a long list of businesses and entertainers announced their opposition and intent to boycott the state, using a combination of economic leverage and moral shaming to nudge elected officials toward backtracking on the issue.

For far too many contemporary liberals, that kind of informal, grassroots pressure from civil society never seems to be good enough. Too lazy and impatient to do the hard work of formulating arguments and trying to persuade, and too addicted to sanctimonious displays of moral righteousness, these liberals now prefer to use the ever-expanding edifice of anti-discrimination law to impose edicts from the top down.

Such liberals get to enjoy the satisfaction of reenacting the civil rights movement every few years, holding up victims of ever-new forms of discrimination as heroes of a great moral saga and demonizing those on the other side as bigots. Once the courts accept the narrative, the logic of anti-discrimination locks in, new rights become codified, and the former victims of injustice get to enjoy total victory while decades or centuries of communally based norms, practices, and beliefs get pulverized.

All for the sake of bending the arc of history a few more millimeters toward justice.

But of course this way of portraying the process is self-justification on the part of the victors, designed to make it sound as if the sequence of events unfolds in the way it does all on its own, because it's what self-evident moral truth indisputably demands. In reality, such battles take place because of choices made by elected officials, bureaucrats, and judges to accept as legitimate and compelling the arguments of activists who favor the change — arguments that until very recently were often summarily dismissed by many of the same people.

Which means that senior members of the Obama administration, and likely the president himself, decided a few weeks ago that this was a good time to pick a fight with cultural conservatives.

One possibility is that he did it without concern for the political consequences — perhaps because after stalling and dissimulating on same-sex marriage for several years, he's resolved not to do the same thing with regard to the next item on the LGBT agenda.

The other possibility is that the president has seen polling data showing that the conservative side of the culture war is even weaker than it is widely presumed to be. In that case, perhaps he thinks the political consequences of his strong stand on the transgender issue will be minimal to nugatory, or maybe even positive.

Whether or not Obama believes he has data to back him up, I think the move was extremely foolish and likely to haunt the Democrats in November.

But even if that isn't the case — even if the bathroom wars somehow redound to Hillary Clinton's benefit — the choice to use the power of the federal government to coerce people to conform with moral decrees from on high (once again, and so soon after the Obergefell decision rooting same-sex marriage in the Constitution) was a mistake.

I supported gay marriage for 10 years before it became the law of the land. I think opposition to allowing transgendered people to use the bathroom of their choice is silly and sometimes cruel. But there's more than one way to win an argument. And in all but the most egregious cases of injustice, liberal governments should resist the urge to prevail through force.