The Solano County Board of Supervisors voted 3-2 in June 2009 to begin implementation of the state-mandated identification card program for medical marijuana patients. The Solano vote comes more than five months after the medical marijuana advocacy organization Americans for Safe Access (ASA) filed a lawsuit against the county for failing to implement the ID card program, which provides increased protection for patients. In January 2009, at the time the lawsuit was filed, twelve counties including Solano had still refused to comply with the requirements of the 2004 Medical Marijuana Program Act (MMP).

The refusal to implement state law was spurred by San Diego County, which filed a lawsuit in 2006 challenging the state's ID card mandate. However, a landmark decision in July 2008 by the California Fourth District Court of Appeal ruled in favor of patients' rights. "Solano had come to the end of its legal rope, with no recourse but to obey state law," said Joe Elford, Chief Counsel for ASA, the organization that also helped litigate the San Diego case. "More than twelve years after the passage of California's medical marijuana law, it's time for local officials to respect the legal rights and protections afforded to patients."

For years, local officials have tried to use federal law as a reason to deny patients their legal rights, but the July 2008 landmark decision in the San Diego case made clear that federal law does not preempt the state's medical marijuana law. After the landmark appellate court decision, both the California Supreme Court (in October 2008) and the U.S. Supreme Court (in May 2009) refused to hear the case brought by San Diego County.

According to the State Department of Public Health's medical marijuana program, fifty-two of California's 58 counties have now either implemented the ID card program or indicated they will soon. However, there are six counties (Colusa, Madera, Mariposa, Modoc, Mono, and Sutter) that have not yet explained their recalcitrance or intent to implement the program. ASA has written letters to officials in these counties threatening litigation if they continue to resist compliance with state law.

According to the MMP, qualified medical marijuana patients and their caregivers can obtain state-issued ID cards under programs administered by each county. The ID cards assist law enforcement in verifying the legal status of patients and caregivers and are supposed to provide protection from arrest and prosecution. However, because of an unwillingness by many counties to implement the program in a timely way, thousands of patients have been placed at unnecessary risk. Another impediment for patients being able to obtain the state ID card is cost. Solano County voted to assess a $200 fee for the card ($100 for patients on Medic-Cal), which is high compared to other counties and may be prohibitively expensive for many patients.