The last time a portion of an existing state broke off to form a brand new state — henceforth known as West Virginia — was in the 1860s, and the contested issue was slavery.

So what issue of overriding gravity has goaded some Weld County commissioners into declaring their desire to secede from Colorado along with other rural counties and form the new state of North Colorado?

Would you believe a mandate for additional renewable energy, which Gov. John Hickenlooper signed last week?

The commissioners have other beefs, of course, including a few modest gun control laws that will stop no law-abiding citizens in Colorado from arming themselves for self-defense. And there is also the prospect — the prospect, mind you — of oil and gas legislation that might impact high-intensity drilling areas but which in fact failed this year.

Indeed, the commissioners’ list of “injuries and usurpations,” to adopt the ringing language of the Declaration of Independence (whose authors could in fact catalog an impressive list of offenses by the British king), is so thin and pallid compared to what one would expect from a genuine secessionist movement that we can’t help wondering, Can these fellows even be serious?

“What I would say to those people in Denver who say this doesn’t have a chance, [that they’re] not going to take this seriously, is beware, because we’re not going away,” commissioner Sean Conway declared Thursday.

If Conway means rural officials aren’t going to stop standing up for their interests and values, then good for them. That’s what they should do. But if he means they’re not going to drop this secession talk, then he’s setting his constituents up for a huge waste of time and effort.

It’s unlikely enough that rural counties could somehow obtain approval from Colorado voters — which might be required because the state’s borders are outlined in the Constitution — and then the legislature and governor. But even assuming the counties overcame that formidable checklist, the idea that Congress and president would allow the creation of a new state with only a few hundred thousand residents and two inevitably Republican senators simply defies logic.

It’s not happening.

Meanwhile, the commissioners’ initiative undermines their own agenda. Many people — not just liberal Democrats — are rolling their eyes and snickering at the secession news, considering it a kooky proposition wildly disproportionate to the alleged grievances.

Serious people with serious complaints don’t waste their time on quixotic crusades. They roll up their sleeves and deepen their efforts to convince their fellow Coloradans that their arguments have merit.