If I want to legalize medical marijuana in my state how do I set it up for taxes to be tax exempt political campaign?

The missouri ethics commission says it would be a pac or continuing campaign committee. But I am unsure as to what entity it would be under in order to get an Ein number for irs. Non profit 501 c-3? Or 501 c-4? Would it be tax exempt? I suppose the federal would be one of these classifications and the state would be a. Pac/continuing campaign committee. Then the local election authority would probably have it's own classification that is required by the state to file as well. Just unsure. Because all the mo ethics commission requires is to have a bank acct. all the bank requires is an Ein number. I could file it as an "other" entity and write down pac on the application.