Can we have a serious talk about secession for a moment?

I know, talking about secession makes about as much sense as discussing what clothes I should bring on a trip to Neptune. Both are far-off possibilities.

But American separatists are in it for the long haul. Though the recent defeat of the independence referendum in Scotland should have disheartened them, at least one pro-secession group is not deterred.

In a recent piece on the CNBC website headlined “Texas independence MUST happen,” Daniel Miller, president of the Texas Nationalist Movement, notes that 10 years ago, no one in Scotland would have thought it would hold a referendum on independence from England. So, Miller’s logic goes, nothing is so far-fetched that it can’t eventually happen, and the secessionists have us right where they want us.

On its own website, the organization accused the news media — incorrectly, it turned out — of being “relatively quiet” regarding the Scottish vote because it knows secession fever is contagious.

“Look at what happened when the southern States of America began to break away. One by one, they followed,” the website says. That’s a strange comparison to choose, given how badly things turned out for the states that left.

But while secessionists muse about a future when the Lost Cause may finally be won, we should remember one thing about the disunion they’re aiming for: It’s not going to be like last time.

In the 1860s, only white men exercised political power. Since then, suffrage has been extended to women and African-Americans. There is no bar to immigrants gaining citizenship no matter what country they came from.

In 1860, Abraham Lincoln didn’t even bother to get on the ballot in most Southern states. In 2008, by comparison, Barack Obama won 40 percent of the vote in Louisiana and 44 percent in Texas. You can find similar results in other former states of the Confederacy, and Obama actually won three Southern states in 2008 and two of them again in 2012.

It doesn’t take a canny political mind to conclude that just about all of those voters would oppose secession. We can also assume that many conservatives, no matter how much they think the country is headed in the wrong direction, would have trouble supporting a movement that dismembers the United States.

So a graphic representation of what was called the “solid South” when segregationist Democrats had an unbreakable hold on the region would look today more like a splotchy heat map showing constellations of pro- and anti-separatist sentiment spread throughout.

What happens to those anti-secession blocs if the states they’re in try to break away?

It’s not hard to imagine New Orleans refusing to follow the rest of Louisiana in leaving the union. The same could be true of heavily Hispanic parts of Texas. According to the Census bureau, Hispanics — as imprecise as that term may be — make up nearly 40 percent of the population of that former republic west of the Sabine.

Black population clusters in states considering secession could be centers of a rebellion within the rebellion.

Secessionists are patient, as the Scottish experience shows, and there’s another example of this even closer to home. When a referendum to separate the French-speaking province of Quebec from the rest of Canada failed in 1980, the separatists persisted and forced another vote in 1995 (and lost again).

American secessionists may fantasize about a return to 1860-61, when states fell out of the union in sequence like knocked-over dominoes. But they also should realize that, should we get to that point again, things will be different next time.

Dennis Persica’s email address is