A store down the street from my house in Los Angeles put blue plastic fencing around its sidewalk, apparently because its owners were about to start construction. After a few weeks, I realized the store owners weren't building anything; they were blocking homeless people from sleeping on the sidewalk.

My first thought was: What a bunch of jerks.

My second thought was: It must be hard for a store to attract customers when there are homeless people in tents living in front of it.

My third thought was: I'm glad there aren't homeless people here anymore.

My final thought was: I'm a jerk.

The California homeless crisis, which now has reached roughly 60,000 people in Los Angeles County, lately has been inching closer to undeclared war. Drivers have thrown rocks and shot pellets at people sleeping in tents. Owners and renters have installed impediments of all kinds to keep the homeless away.

The city of Los Angeles sent investigators from its Bureau of Street Services to count the illegal fences, planters, thorny bushes and cactus gardens put up by stores and homeowners. They found 299 of them, with more going up every week. Some 7-Elevens are installing speakers outside and blasting classical music to drive vagrants away.

Last week, the U.S. Supreme Court declined to take up an appeal of a Boise, Idaho, case which had held the city cannot issue tickets to homeless people for camping illegally in public. The decision is a reminder that city governments are desperate for any tools they can use.

I sat down for tea with Christopher Homand­berg, a Los Angeles lawyer who specializes in renters' rights and helped start Ktown for All, a homeless organization in Koreatown, back in January. In his free time, he scouts his gentrifying neighborhood near downtown for illegal fences and planters; he's registered more than 100 complaints to the city.

As we leave the tea shop, a place he likes and suggested, he shakes his head, noticing someone had lain in a bed of gravel on the sidewalk. Then he takes me on a guided tour of what might be called "homeless prevention technology."

Nearly every sidewalk in this part of Korea­town has been festooned with potted plants, four-foot-high plastic fences, cactus gardens or small trees. "They're not trees," Homandberg says, correcting me. "They're swordlike plants." A parochial school went with both fences and sword plants.

Often, a block of storekeepers or homeowners will agree to call 311 to clear off a group of tents, citing the "bulky items" ordinance that prevents people from keeping belongings on the sidewalk that can't all fit in a 60-gallon trash bag. Landscapers wait for the cops to arrive and, while the homeless put their belongings into the bag, they install the planters. Homandberg lodged a complaint that the planters are themselves illegal bulky items. The city didn't go for it.

The founding father of the planter movement is Mark Ryavec, a lobbyist and founder of the Venice Stakeholders Association. When an employee of his City Council member suggested at a neighborhood meeting that the residents deploy sidewalk planters to fend of homeless, Ryavec objected. Not because it seemed cruel, he explained, but because he thought the city was ducking its responsibilities. "You're expecting us to spend all this money to solve a law enforcement problem," he said.

But in desperation, his group soon began buying planters. "It's a form of soft vigilantism. It's saying the police no longer will protect us, so we have to protect ourselves."

His group raised $35,000 for its first 55 planters and has since put up more. The planters are nice, he says, noting that a professional photographer had a couple pose in front of one for an engagement photo.

Ryavec, whose brother died from addiction, seems to have used up his well of empathy, like many in California.

"When they're raging at each other at 2 in the morning and frightening your 5-year-old child, the side I come down is the family with the 5-year-old kid," he says.

Ryavec thinks Homandberg and his friends who are buying homeless people tents are making the problem worse: "They see the homeless as victims of capitalism as opposed to mental illness or drug addicts or young travelers who don't want to be housed. They are literally choosing this lifestyle. They're hippie backpackers who've gone one more step into an anti-establishment mode."

When City Council President Herb Wesson passed a motion to "investigate and remove illegal fencing citywide," what the mayor's office wound up with was a ruling that required landowners to get a permit for any new planters. Most will get them. "We're trying to thread a very small needle," says Brian Buchner, the mayor's chief of homelessness operations and street strategies, which is a title that tells you a lot about the shape of things here.

Mayor Eric Garcetti, a Democrat, has made fixing homelessness a priority, but he can't build housing and shelters fast enough to keep up with the influx. And he's frustrated by people who want the problem fixed and yet protest shelters being built in their neighborhoods.

So, for now, the city government has to perform the same difficult moral calculus I did when looking at that fence in my neighborhood.

Joel Stein is the author of "In Defense of Elitism: Why I'm Better Than You and You're Better Than Someone Who Didn't Buy This Book." He wrote this article for the Washington Post.