Known as the "first in time" rule, the mandate forces landlords to rent to the first qualified applicant, rather than choosing the best fit from among prospective tenants.

With a heavy-handed new law that is the first of its kind in the nation, Seattle has set its regulatory crosshairs on landlords, attempting to police their inner thoughts and eliminate the possibility that their decisions could be motivated by "implicit" or unintended bias.

Sponsors contended that this unprecedented restriction is needed because traditional anti-discrimination laws do not protect against unconscious prejudices. Landlords, it was alleged, can't be trusted to make decisions based on their "gut instincts," because there's no way to know whether those instincts are "pure." The only solution is to take away their right to make discretionary decisions altogether – including decisions based on rational, nondiscriminatory considerations.

The new rule has just drawn a lawsuit from a number of mom-and-pop landlords, based on its infringement on constitutionally protected property rights. But its assault on good sense is just as compelling and should serve as a warning to the rest of the country.

While equal access to housing is a laudable goal, Seattle's attempt to regulate how rental property owners think is misguided and will ultimately limit housing opportunities rather than expand them.

Landlords often rely on gut instincts when choosing a tenant, for legitimate reasons. Consider Chong and MariLyn Yim, who own and live in their Seattle triplex with their three children and are plaintiffs in the lawsuit. Because they share a yard with their tenants, they want to carefully select the most appropriate applicants to ensure they will get along with the Yims' children. But the city is denying them that freedom.

Kelly Lyles, another plaintiff, is an artist who needs the income from her rental property so she can afford to live in Seattle. As a single woman and building manager who frequently interacts with her tenants, she has to take her personal safety into consideration when choosing them. "No business would be told they have to hire the first person to show up with a decent resume," said Ms. Lyles. "This law would be ridiculous if it wasn't so frightening!"

Depriving landlords of discretion – the ability to act on gut instincts – can harm the very population the city says it is trying to help: financially challenged people who struggle to find housing. For instance, small property owners Scott Davis and his wife rented out an apartment in a desirable neighborhood to two young men, both minorities, who were recent graduates with no solid rental or credit history. The Davises decided to give them a chance because of their polite and impressive demeanor. They have been solid tenants for three years. The Davises have joined the lawsuit because the new law prohibits them from exercising that kind of humane flexibility.

Officials knew full well that the law is overbroad and will hurt upstanding landlords who base their decisions on legitimate, nondiscriminatory factors. But promoting a political and social agenda was too important to let that get in the way. According to City Council member Debora Juarez, the law will ensure that landlords do not "cherry pick which residents they deem 'worthy' and ... [will] level the playing field for those looking for housing." Council member Lisa Herbold said it will "limit the likelihood of creaming the application pool and going through a stack of applications to find the best one even if [the landlord has] already identified somebody ... that meets their qualifications." Outlawing choice and discretion, in her view, can help landlords "unlearn" any "implicit associations" they may have.

Landlords like the Yims, the Davises, and Ms. Lyles are simply collateral damage from the city's desire to "unlearn" its citizens.

While the city clearly has authority to prohibit overt discrimination by landlords, the concept that government should try to regulate an individual's unconscious thoughts is dubious at best.

As the courts are likely to find, Seattle's scheme to impose that concept also happens to be unconstitutional. Denying landlords any say over who lives in their property robs them of a fundamental right of ownership.

In adopting the law, the city acknowledged that it has no idea how many rental decisions are made based on unconscious bias. Regardless – or perhaps because of that – the city decided to treat every landlord as if he were prejudiced and incapable of selecting tenants without government oversight. It's like trying to prevent fistfights by shackling everybody's hands.

Seattle officials are boasting about being national leaders with this law, but it's no distinction to be first with regulations that cause more harm than good and take fundamental freedoms away.

Brian T. Hodges is a managing attorney with Pacific Legal Foundation, a property-rights watchdog organization that represents the mom-and-pop landlords who are challenging Seattle's "first in time" rental law.