Your wife can have the union deduct that portion of her dues that go toward union political activity. They won't tell her that, but it's federal law, since I think the Beck decision. My wife did that with the correctional officer's union in Cal.
I tried that. They told me that the amount each month was $6. Out of the $75 that was forcibly taken from my check each month. To opt completely out of the union, I would have had to pay the entire dues up front, before school started. I took an $8000 pay cut to start teaching and didn't have the $900 my old union is allowed to steal from a teacher's paycheck, since I was busy paying back the $5000 in tuition it cost me to take the worthless "teacher training classes" to become a teacher in the first place.
Want to break the unions? Support legislation that makes it really possible for teachers to opt out of unions, and that doesn't let the union steal the money anyway.
I moved to Indiana, and since that legislation passed here, union membership is extremely low. It's only 10% at my school. I would never join.