The recent legalization of recreational cannabis in Illinois was tied to the imposition of a number of new taxes imposed at the state, county, and municipal level. A recent bill, if passed, would also authorize library districts to impose their own 1% tax on the sale of recreational cannabis. HB 4135.  
If a library district imposes such a tax, the bill mandates that any applicable tax imposed by the county in which the library district is located be reduced by 1% and that all municipalities in the county in which the library district is located must also reduce their cannabis tax by 1%. 
That mandatory reduction in county and municipal cannabis taxing authority is likely to raise some concerns with those governmental units that have already enacted a county or municipal cannabis tax, particularly since the proposed legislation is written so broadly as to seem to apply to all municipalities in the county in which the library district is located, without regard to where the library district is located.