San Francisco is once again leading the way – this time with a proposal that would appear to make it the first county in the nation to unequivocally refuse to detain immigrants suspected of living here illegally for federal authorities. That proposal, authored by Supervisor John Avalos and supported by a supermajority of his colleagues, would make it illegal for San Francisco law enforcement officials to detain someone solely on the basis of immigration status. Currently, the Sheriff Department’s policy states that only people suspected of serious or violent felonies, or those with a serious or violent felony in their past, will be held for immigration authorities. In 2012, 542 people were handed over to federal authorities by San Francisco officials; another 176 were transferred in the first six months of 2013. The proposed law will be considered by a board committee made up of its supporters Thursday, where it is expected to be approved.