SANTA MONICA, California — The average one-bedroom apartment in this beach town will cost you more than $3,700 a month, according to one recent study. The median home price here was $1.1 million in 2017, according to census data, and 90% of the homes here cost more than $500,000.

It’s one of America’s most expensive places to live in. That’s one reason that there’s a massive homelessness problem here and in the broader Los Angeles County. "The number of homeless people counted across Los Angeles County jumped 12% over the past year," the Associated Press reported last year, "to a total of 58,936."

Homelessness has many causes, and few of them are easy to work through. Addiction and mental illness are two. Family and community breakdown are two more. Drawing the homeless population to Santa Monica specifically are laws that explicitly permit sleeping on sidewalks.

But one cause of homelessness is a simple lack of homes. And Santa Monica, like much of California, has fewer homes than it should — thanks to regulation.

Land-use regulations make housing more expensive. The Los Angeles metro area ranks as the 15th most restrictive in land-use regulation.

People who own houses in housing-restricted places often don’t want to deregulate. They like the space. They fear the traffic. And they know that adding more housing could harm their home values. Of course, preserving scarcity in housing to keep your housing investments valuable is not really something most people want to admit to, so they make other arguments. They suggest that the regulations drive up home values not by curbing supply but by giving people what they want: green buildings, safe buildings, adequate parking, and uncrowded neighborhoods.

But the one study that has looked into this finds that more than 90% of the price effect of regulation comes not from making the homes more desirable but from limiting supply. So regulation is affecting the market mostly by preventing homes from being built.

Santa Monica is a liberal city that voted 80% for Hillary Clinton in 2016, so it’s no surprise that it’s overregulated. But one would expect liberals to support public policies that help reduce homelessness.

Californians’ liberal values, however, often have exceptions when it comes to their really expensive housing. Recall, for example, how Sen. Dianne Feinstein recently fought to preserve tax breaks for rich people who carry very expensive mortgages.

Gov. Gavin Newsom has taken some laudable steps to deregulate housing, specifically legalizing “granny flats,” second units in lots otherwise zoned for single-family housing.

Californians are willing to do a lot to help their homeless neighbors. But at what point do they accept that this entails deregulation?