My 9-year-old looked up at the fancy treehouse dividing a neighborhood not far from the U.S. Capitol.

“Adults are mad about this?” he demanded, astounded. “This is so cool. We’ve read about a magic treehouse. Is this one magic?”

Maybe. Dark magic, though.

Because this cutesy, overdesigned little treehouse in a tucked-away, narrow pedestrian alley near 6th and G streets in Southeast Washington has done more than spark a neighborhood turf war. It has provided us with yet another example of the country’s growing intolerance for childhood and all the imperfections that come with raising kids.

What else explains the full-throated legal, political and regulative fury over treehouses, lemonade stands, a rural back-yard ice rink and other kid-fueled enterprises?

This Capitol Hill treehouse has sparked debate among neighbors, with some saying it shouldn't have been constructed 20 inches over their property line into the alley. (Larry Janezich/Capitol Hill Corner)

Meanwhile, we’ve got shows such as “Treehouse Masters” — a parade of ultimate adult treehouses with hot tubs, martini bars, A/C and big-screen televisions. Even Dale Earnhardt Jr. has one.

But you, young children who live next to grumperella? Not for you.

[This treehouse extends 20 inches into an alley, and it’s dividing neighbors]

The parents who built the Capitol Hill treehouse for their daughters, ages 3 and 5, checked with the city on permits before constructing their little castle in the sky. It sits in an elm tree on their property that has branches that extend into the alley. The treehouse, which looks more Pottery Barn Kids than Henry Huggins, is about 10 feet off the ground and juts into the alley by 20 inches.

This isn’t the corrugated steel, wood scraps, tar shingles and carpet remnants of the treehouses of my youth. It’s actually nice (and safer). And given that it’s in view of maybe eight neighbors, probably the stuff that went down in our ’70s treehouse won’t happen there.

But the alley, Archibald Walk, is one of those little spaces that’s all artsy-fartsy-wine-party-eclectic. The neighbors put out potted plants and benches, there are little statues in wall alcoves and colorful tiles. The bollards leading up to it have been painted in carnival stripes. It’s like a feature in Southern Living where they charm up urban alleys. Once, when I was picking up the kids from their tae kwon do class in the church next to the alley, there was a full-on disco ball party happening there.

All weekend, a parade of visitors gawked at the treehouse and debated its merits.

“Oh, it’s not that bad. It’s kind of charming,” a woman said.

“It doesn’t belong,” her husband ruled. “The law says it doesn’t belong.”

It’s the city, move to the suburbs if you want a treehouse, a lot of other folks said.

But it’s happening in the ’burbs, too.

There were two recent battles in Northern Virginia where folks were cited and treehouses on private property had to be torn down when neighbors didn’t like what they were seeing.

In Pennsylvania, a 14-year-old girl who engineered and built an amazing treehouse in her suburban front yard had to dismantle it because officials decided it was against town regulations, which make no mention of a treehouse and were studied extensively by Elisa Truchan’s family before construction began.

[Inspectors may close a backyard ice rink honoring a stepdaughter’s memory]

This kind of adulthood buzzkill is also about to whack a back-yard ice rink in Poolesville, Md., that has been a magnet for kids. Officials intervened because the synthetic rink sits in an agricultural reserve, which doesn’t permit public use.

How about the wave of crackdowns on lemonade stands? Kids across the country have been shut down and fined for not having permits to sell.

Way to go, grown-ups, for trying to kill important parts of becoming an adult: discovery, risk, independence.

I recently chaperoned a field trip to a museum. After the kids were attentive and well-behaved inside, we took them over to a public space to play. They organized games of sharks and minnows and freeze tag, zigging and zagging and, yes, occasionally whizzing past museum-goers out for a stroll. The other parents and I were on edge, waiting for a not-amused adult to holler.

Sure enough, there she was. An older woman in her going-to-a-museum whimsical scarf unlinked arms with her husband and headed right toward us across the lawn.

“Are these children with you?” she asked.

“Um, yes,” we chirped.

“Well, I want to congratulate you. It is so refreshing to see children acting like children. To see them run and play outdoors. To hear them laugh and scream,” she said. We exhaled so hard we nearly knocked her over.

“It’s so much better than having them closed away and with their electronics, not bothering anyone.”

Right on, museum lady.

Hear that, folks?

There are times to let it go, to embrace — or at least accept — the messier aspects of children’s lives. To give an inch, or maybe 20.

Twitter: @petulad