Facing an uphill battle, proponents of a ballot measure to legalize marijuana are mapping out a campaign stressing the millions of dollars in tax revenue that pot could provide.

The initiative, sponsored by Oakland marijuana magnate Richard Lee, would legitimize the sale of marijuana and allow pot shops to open their doors in cities that permit it. Local authorities could also decide how to tax and regulate marijuana sales, although it’s unclear if federal officials would tolerate such a bold and unprecedented move.

Many of the state’s most important politicians want nothing to do with the measure, which would allow anyone over the age of 21 to grow or possess a drug considered by the federal government to be highly addictive and of no medical value.

Despite lawmakers’ reluctance, political consultants working on the initiative claim a marijuana tax could contribute more than $1 b