In the wake of Massachusetts’ recent marijuana legalization,

State Senator Jason Lewis plans to introduce legislation next month that would prevent workers from losing their jobs solely for consuming marijuana on their own time.

Despite supporting marijuana legalization, libertarians should oppose this legislation.

First, employers should be free to fire employees for any reason, subject only to any contractual relation between the two.

In addition, leaving employers free to fire workers for off-hours use will enhance public support of legalization. A common concern is that employee marijuana use might generate work accidents or other unproductive behavior. Employers can address this concern, in part, by testing for at-work use.

But the line between off-hours and at-work use is murky, so creating a legal distinction will be messy. This implies on-going concern that some employees use at-work, weakening support for legalization.

Market dynamics, moreover, will discourage employers from testing for off-hours use unless such testing truly predicts employee productivity. Testing is costly, and if many employees find it annoying, employers who use it will face higher wage costs.

The right policy is therefore freedom for marijuana users and freedom for employers who, for whatever reason, prefer employees who do not use marijuana off-hours.