I suppose this is not a surprise to most people.
The teachers unions give mostly to Democrats and in national elections nearly exclusively so. Their legislative agenda for education continues to focus on increasing spending, loosening accountability for results, avoiding the use of test scores in teacher evaluations and thwarting parental choice that could derail the public education monopoly….
So teachers unions are spending millions in dues revenues on legal fees suing to block charter schools and other parental-choice reforms. Charter schools have emerged as primary targets for the wrath of teacher-union leadership largely because charter teachers rarely belong to unions.
Graph from opensecrets
Found at Instapundit