And the sign said ...

This will surely come as a surprise to the millions of motorists who cruise past the Adopt-a-Highway mini-billboards, but the California Department of Transportation says the litter cleanup program is not a forum for advertising or “public discourse.” If that’s the case, why all those nifty little signs naming the local litter-pickers? Given the scarcity of signs announcing anonymous do-gooders, the program clearly works because it gives some businesses and groups a little publicity at the same time that it helps clean up the roads.

That’s most likely what the San Diego Minutemen -- a different anti-illegal-immigrant group from the Orange County-based Minuteman Project -- had in mind when members adopted a stretch of Interstate 5. It was the nearest available to their location in Vista, but, as they discovered, that particular stretch included a Border Patrol checkpoint in Camp Pendleton. And they might have gotten a little more notice than they expected.

After complaints from immigrant-rights advocates, Caltrans yanked the sign in January with plans to plant it along a road less traveled. The Minutemen sued in U.S. District Court, claiming infringement of their right to free speech, and the sign was restored last month after a judge’s order.

It was the right move. We are not fans of Minutemen either plural or singular, or similar vigilante groups. But as long as they pick up trash and don’t make a public spectacle of themselves on I-5, they have a right to their sign.

Caltrans failed to follow its own Adopt-A-Highway rules, which prohibit participation by individuals or organizations that advocate violence, breaking the law or discrimination against people based on race, religion and so forth. The rules are reasonable; because discrimination against those protected groups is illegal, the state cannot become the means to spread such messages. But illegal immigrants are not among the protected groups.

Caltrans at first defended the sign on free-speech grounds, but then backed down, claiming that the sign would become a public nuisance. Strange, because a Minuteman Project sign along California 133 in Irvine has created no such problems.

Now Caltrans is holding off on all new Adopt-a-Highway permits while it reviews its rules. In doing so, transportation officials ought to either recognize that the program is indeed a vehicle for publicity or take down all the signs. Once the agency opens its highways to promotional signs, it cannot discriminate because its officials or others don’t like a particular group.