On Thursday, the Supreme Court agreed to hear a case that could deal a crippling blow to public sector unions.

The case, Janus v. American Federation of State, County and Municipal Employees, challenges the constitutionality of "agency fees" or "fair share fees" — financial dues required of all workers regardless of union membership.

Unions argue this prevents non members from benefiting from collective bargaining efforts without contributing to the fund. Challengers, like Mark Janus, the plaintiff in this case, say it violates their First Amendment rights.

Adam Liptak, Supreme Court reporter for The New York Times, explains. 

This segment is hosted by Todd Zwillich.