Supreme Court ruling and CFT/AFT

The Huffington Post reports that a new case before the Supreme Court might make "fair share"payments illegal and impact the ability of a union to collective bargain.  Basically, our union negotiates a contract with the district.  Some might not want to pay, but still get the benefits of a raise. 

The article states:  

No one in the U.S. can be forced to join a labor union. The so-called closed shop has been illegal in this country for decades. But where state law allows it, workers can be required to pay fair-share fees to the union, even if they don't want to be full-fledged members. These fees can go toward the cost of bargaining contracts, but not toward political activities.
The fees address what unions like to call the "free rider" problem. In a unionized workplace, the union has to negotiate a contract for everyone in the bargaining unit, even if some people don't want to be members of the union. Since bargaining is expensive, unions argue it's only fair that everyone contribute to those costs. Hence fair-share fees.
If fair-share fees are found to violate the First Amendment, organized labor would run up against personal economics. Although some workers may leave the union on principle, others may stop supporting it financially because they know the union will bargain on their behalf anyway, for free. Workers bail on the union, and the union becomes less effective.
"It would weaken our ability at the bargaining table and on the job, [our ability] to advocate for us and for the community," said Stephen Mittons, president of the American Federation of State, County and Municipal Employees Local 2081, in Chicago. "By decreasing the numbers even slightly, it does add to our vulnerability."
So, if no one is forced to fund a union’s politics in the first place, then how is Friedrichs a First Amendment case centered around political speech? The conservative groups backing the lawsuit argue that, unlike in the private sector, public-sector unionism is political by nature, since unions are negotiating over wages paid expressly by taxpayers. Their argument hinges on that logic.