Los Angeles Teacher Union Counting Votes on Whether to Raise Dues to Pay for "Ideological Activities"

The 32,000 members of the Los Angeles teachers union, UTLA, is counting member votes on whether to raise mandatory dues, which currently average about  $760 per teacher per year. Why is the union leadership pleading for more money? Because, reports the Los Angeles Times,
Union President Alex Caputo-Pearl said that the money will help combat a brand of reform that favors operating schools more like businesses — for example, by using metrics-based performance evaluations such as standardized test scores to rate teachers.
I’m confused. I thought the union’s argument in the Friedrichs lawsuit currently before the Supreme Court was that mandatory dues are not a violation of the First Amendment – in this case the right to personal views on political issues – but instead represent a member’s “fair share” of the costs related to collective bargaining.  But this plea for more money (UTLA pulled in $38.2 million in 2013) is for blatantly political activities like lobbying against charter school expansion, tenure reform, and sponsoring campaigns for pro-union school board candidates.

That seems above and beyond negotiating for salary increases.

A New York Times piece last month quoted the 1977 Supreme Court decision in Abood v. Detroit Board of Education.  Compulsory fees are constitutional , said Justice Potter Stewart, although  “to compel employees financially to support their collective-bargaining representative has an impact upon their First Amendment interest."Such interference as exists," however, "is constitutionally justified” to ensure “labor peace.”

But, Justice Potter added, what crossed a constitutional line was forcing objecting workers to pay for “ideological activities unrelated to collective bargaining.”

Hence my confusion. Isn’t anti-charter school lobbying an ideological activity unrelated to collective bargaining? Isn’t a dues-funded campaign against the use of student growth metrics in decisions about teacher tenure an ideological activity unrelated to collective bargaining?

Sure, one could argue that charter schools have the option of employing non-union teachers, which cuts down on UTLA’s (ever-decreasing) bottom line, which has an impact on its ability to fully man board-union salary negotiations. Or that data-driven teacher evaluations has an impact on job security. But aren’t we crossing the line delineated by Justice Stewart?

The Times piece starts with this anecdote:
Harlan Elrich is a high school teacher in California, and that means he must pay about $970 a year to a labor union. He teaches math, and he said the system did not add up. 
“I get to choose what movie I want to go see,” Mr. Elrich said. “I get to choose what church I want to go to. I get to choose what gym I want to join.” 
He should have the same choice, he said, about whether to support a union.