Voters have passed a controversial San Francisco ballot measure requiring drug tests for most welfare recipients, a sign of a rightward political shift in the historically progressive city.

As of Wednesday, Proposition F, backed by Mayor London Breed, had about 63% support. The measure will require people receiving monthly payments from the citys cash assistance program for the poor to undergo drug testing if they are reasonably believed to be dependent on illegal drugs.

If they then refuse to comply or accept treatment for drug use, they will be deemed ineligible for the benefits.

People with young children and or who are over 65 years old are exempt.

We want people to seek treatment and many people do, but the reality is others are not willing or able to do so, Breed, whos up for reelection in November, said in a statement. Prop F will help get people into care. We are also sending a message that we are a city that offers help but not a city where you can just come and do whatever you want on our streets.

More than 5,700 San Franciscans currently receive benefits, which can be as much as $712 a month in a notoriously expensive city.