EDITORIAL Mayor Gavin Newsom has set off something of a crisis in San Francisco government by insisting that he will defy the city law that seeks to protect immigrant youth from deportation. While Newsom claims that the sanctuary policy approved 8-2 by the supervisors last week violates federal law (something the same-sex marriage advocate hasn't worried so much about in the past), this is really a matter of politics. Newsom, candidate for governor of California, doesn't want to seem soft on crime — so Newsom, mayor of San Francisco, is siding with the federal immigration authorities.

He's also putting out a misleading message about the law.

The sanctuary legislation, by Sup. David Campos, is an attempt to deal with a very real — and serious — problem. Under the city's current policy, any time a young person is arrested and the juvenile probation department thinks he or she might lack documentation, the officers involved contact Immigration Control and Enforcement. That means kids who have lived in this country for years and have no ties to their birth nation can be deported — just on the basis of an arrest that could turn out to be groundless.

Campos' law establishes a city policy that prohibits local law enforcement from reporting juvenile offenders to ICE until they've been convicted of a crime. That's just basic due process.

Newsom insists (and the city attorney's office agrees) that no city employee can be penalized for contacting ICE. But that's not the point of this law. Right now, juvenile officers are required to call ICE when they have someone in custody who may be undocumented. There's no federal law saying this has to happen. And it's perfectly legal — and appropriate — to lift that mandate and to say, in effect, that no city employee should be penalized for declining to turn a kid over to the feds.

At this point, the city attorney hasn't argued that the Campos bill is illegal or unenforceable, and no judge has overturned it. When, as expected, the supervisors override Newsom's certain veto, the bill will become city law — presumptively valid until a court rules otherwise. And Newsom has a legal obligation as mayor to abide by and enforce that law.

City Attorney Dennis Herrera is in something of a bind here since he has to represent both the mayor and the supervisors. But he needs to make clear, in public, that while he warned of possible legal implications of the Campos legislation, right now there is nothing preventing the law from taking effect — and that the mayor, like any other city official, is required to follow it.

The supervisors need to keep pushing the issue, too. And they need to be prepared to go to court to seek a writ mandating that the city's chief executive follow his sworn oath and faithfully execute the law.

None of this needs to happen. Newsom could have worked with Campos on the legislation. Instead, the mayor continues to defy the board and act like the sort of imperial executive who is utterly unqualified for any higher office. For the sake of innocent kids facing the horrors of deportation, San Francisco's reputation as a sanctuary city and Newsom's own political future, he needs to back off and agree to abide by the city's own laws.