Sharma Hammond, a lawyer with the Immigration Law Reform Institute in Washington, D.C., said, "We're discussing whether they would take an appeal, but we do not know yet whether they will."
Hammond called the dismissal of the lawsuit by San Francisco Superior Court Judge Peter Busch on Tuesday "a great disservice to the environment."
Among other arguments, the four citizens who filed the lawsuit claim the program will have an impact on the environment because it will enable illegal immigrants to obtain identification cards and will thus encourage them to settle in San Francisco.
Hammond said, "These illegal immigrants dramatically increase population growth."
The municipal ID ordinance was enacted by the Board of Supervisors last November, but has been on hold while city administrators review the plan.
The program would provide government ID cards to people who can prove their identity and show that they have been present in the city for at least 15 days. It does not require proof of immigration status.
The American Civil Liberties Union and other civil rights groups joined the case on the side of the city to defend the measure.
ACLU attorney Julia Mass said, "The municipal ID program is a modest public safety measure, meant to ensure that all San Franciscans have access to services and police protection."
Mass said, "Our clients are organizations whose members -- as youth, homeless people, immigrants, and transgender San Franciscans --face particular obstacles to obtaining identification cards.
"Access to ID cards is important for all San Francisco residents to feel comfortable reporting crime and standing up for their rights," the attorney said.