Hillary Clinton knows she has more baggage than Newark Airport. She doesn’t care, because she is counting on two strong forces to carry her to victory: Demographics and the leftward turn in American culture.

She and the other Democrats suffer from cultural hubris, though. Their social justice wings always threaten to take them a little too close to the sun.

Even if all enemies are vanquished, the progressive wars can never be won. The Democrats will always find new hostile territory to invade, always creating a New Frontier.

Two weeks ago I wrote about a massive, silent cultural revolution in American attitudes: Since just the middle of the last decade, there has been a huge increase in support for gay marriage, legalized marijuana and single parenthood.

These changes favor Democrats, as does increasing ethnic diversity. Mitt Romney won the same percentage of white Americans on election day of 2012 as Ronald Reagan did in 1980. Reagan became president in a landslide. Romney was seen pumping his own gas the following week.

Yet as the parade veers left, the Democrats must always race out to be in front of it. This week’s Gallup poll says that a record high 47% of Democratic voters identify as both socially liberal and economically liberal or moderate. That’s up 8 points since the 2008 election of President Obama and 17 points since 2001.

Just as yesterday’s luxuries become today’s necessities, Democrats are continuously redefining what it means to be Democrats.

They celebrate their many gay-marriage victories, with a final, 50-state resolution due soon, perhaps any day now. But that won’t be the end of the issue. As recently as early 2012, even Obama opposed gay marriage. Within 15 minutes after he publicly reversed course, liberals were routinely comparing gay-marriage opponents to racists, and 30 seconds after that liberal judges started forcing evangelical bakeries out of business for declining to participate in gay weddings.

Just this spring, Obama’s own solicitor general let slip that “it is certainly going to be an issue” whether universities that decline to back gay marriage will be able to retain their tax exemptions.

If such exemptions are henceforth made conditional on offering hearty support for same-sex unions, by what logic would churches that oppose homosexuality be able to retain their tax-exempt status?

We’ve already seen that the First Amendment’s guarantee of religious freedom couldn’t save a Christian bakery.

Could Catholic priests be forced to marry Adam and Steve? “Not a chance,” declared Slate’s Emily Bazelon in a sneering column that said this was a mere “scare tactic.” Political sci-fi. You might as well fear an invasion of zombies.

That was 2¹/₂ years ago. Two months ago, gay New York Times columnist Frank Bruni pushed the goalposts down the field. He wrote approvingly of Mitchell Gold, a gay philanthropist and founder of the activist group Faith in America, which is dedicated to stamping out what it calls “religion-based bigotry.” Gold says churches must “take homosexuality off the sin list.”

Last year an essay by The Atlantic’s Ta-Nehisi Coates touting reparations payments for black Americans was warmly received by the left-wing intelligentsia. Yet in a YouGov poll, only 6% of white voters agreed that blacks deserve cash payments, while 59% of black voters think so.

How much longer will Democrats be able to forestall talking about an issue that receives strong support from their base? It’s not hard to picture Bernie Sanders clobbering Clinton with the idea in a debate.

And, by the way, Sanders’s self-identification as a “socialist” no longer marks him as extreme, at least to Democrats. Forty-three percent of Democrats say they approve of socialism, the same percentage who like capitalism. The public, to say the least, does not agree: By a margin of two to one, they preferred capitalism to socialism in a May YouGov poll.

We’ve already seen that the First Amendment’s guarantee of religious freedom couldn’t save a Christian bakery.

Obama supports a federal minimum wage of $10.10 an hour. Hillary Clinton has moved far to the left of that, seemingly endorsing a $15-an-hour wage floor in a call to fast-food workers this month. On free trade, which is backed by Obama, was a core policy of her husband’s administration and which she herself has supported many times in the past, Clinton is suddenly silent.

In order to lock down Latino support, Clinton has staked out a position to the left of Obama’s extreme position on immigration, and less than 48 hours after arsonists in Baltimore burned down an innocent CVS store, she said “it is time to end the era of mass incarceration,” marking herself as perhaps the first president ever to run overtly as a friend of the criminal class.

The media often remind us that Democrats and Republicans used to forge bipartisan policy solutions, scolding Republicans for supposedly moving right.

But if the center is becoming a lonely place in American politics, Democrats are walking away from it much more rapidly than Republicans are.