Planners, like all professions, have their own useful mythologies. A popular one goes something like this: “Many years ago, us planners did naughty things. We pushed around the poor, demolished minority neighborhoods, and forced gentrification. But that’s all over today. Now we protect the disadvantaged against the vagaries of the unrestrained market.” The seasoned—which is to say, cynical—planner may knowingly roll her eyes at this story, but for the true believer, this story holds spiritual significance. By doing right today, the reasoning goes, planners are undoing the horrors of yesterday.

This raises the question: are planners doing right today? That’s not at all clear. Just ask Hinga Mbogo. After emigrating from Kenya, Mr. Mbogo opened Hinga’s Automotive in East Dallas in 1986. Mr. Mbogo’s modest business is precisely the kind of thing cities need, providing a service for the community, taxes for the city, and blue-collar jobs. While perhaps not of the “creative class,” Mr. Mbogo and his small business represent the type of creative little plan that cities cultivate and depend on. Hinga’s Automotive has thrived for 19 years and looked primed for another 19.

Unfortunately for Mr. Mbogo, Dallas planners had other plans. In 2005, the city rezoned the area to prohibit auto-related businesses. While rezonings—particularly upzonings—aren’t necessarily a bad thing, Dallas planners opted to force their vision through and implemented a controversial planning technique known as “amortization.” Normally when planners rezone an area, they allow existing uses that run afoul of the new code to continue operating indefinitely. These are known as “non-conforming uses” and they’re common in neighborhoods across the country, often taking the form of neighborhood groceries, restaurants, and small industrial shops. Yet under amortization, the government forces non-conforming uses to cease operating without any compensation. In the case of Hinga’s Automotive, this means Mr. Mbogo must shut down his thriving business.

You might be asking, what has Dallas officials bullying immigrant entrepreneurs? The sad truth is that the rezoning was expressly designed to gentrify the area. As one city council member awkwardly put it, the hope was to attract hip urban businesses “like Starbucks and Macaroni Grill.” In a bizarre turn of events, even the staff of the Dallas Morning News have taken to berating the man. Mr. Mbogo’s greatest sin is not that he hurt anyone. He and his business simply didn’t fit into the plan. It’s a familiar story to anyone who has studied planning history and it’s a familiar story to anyone who follows planning practice today. Wherever the minutiae of city life is controlled and regulated by a political process, small plans—particularly those of marginalized groups—will never be safe.

This particular form of planning mythology is important even if it is false today. Planners did displace thousands of low-income Americans, force sprawl and automobile dependence, and undermine the small businesses that make for healthy cities. But at least in the realm of land-use regulation, redemption doesn’t mean more control—it means less. So long as planning commissions and city councils are empowered to segregate uses and push around the weak, they will. If urban planners want to undo the damage they have wrought, they can start by taking apart the system they created.

P.S. Mr. Mbogo isn’t taking this facing down. With the help of the Institute for Justice, he is taking Dallas to court to defend his rights. Learn more about the case and how you can get involved.