The U.S. Supreme Court ruled in 2005, however, that federal authorities could continue under federal law to prosecute California patients and providers engaged in the cultivation and use of marijuana for medical purposes.
A quick guide to using the colon. A colon is made up of two dots, one placed above the other. One common use of the colon is to introduce a list of items. For example: To make the perfect jam sandwich you need three things: some bread, butter and strawberry jam. Three items are listed in the sentence above.
This is what the Penguin's Writers Guide: How to Punctuate by George Davidson (2005) has to say about the semicolon: In introducing lists, a colon is used when all the options are specified, whereas a semicolon is used when only some of the possible options are mentioned: The Gauls were afraid of only one thing: that the sky might fall on their heads.