Does the Constitution allow a public-sector union to enter into a contract with a state employer that restricts a public employee's constitutional right to resign his union membership?

question presented is: Does the Constitution allow a public-sector union to enter into a contract with a state employer that restricts a public employee’s constitutional right to resign his union membership? 1. Agreement Between the State of California and California Statewide Law Enforcement Association (CSLEA) Governing Bargaining Unit 7 (2016-2019), article 3.1A1, Dkt. Entry 50-1, at p. 16. (i) 2. On December 17, 2013, Mr. Cooley typed his initials on an online union-membership application that contains the following sentence: “Per the Unit 7 contract and State law, there are limitations on the time period in which an employee can withdraw as a member.” The district court and the Ninth Circuit held that this document established a legally binding contract, and that the terms of this contract obligated Mr. Cooley to remain a member of the CSLEA until June 1, 2019. App. 3a; App. Ya-l1la. But the “Unit 7 contract” that existed at that time was the 2013-2016 agreement between the union and the State, not the 2016-2019 contract that purported to prevent Mr. Cooley from resigning his union membership until June 1, 2019. Under the terms of the 20132016 Unit 7 contract, Mr. Cooley was required to maintain his union membership only until June 1, 2016.’ The question presented is: Did Mr. Cooley promise to maintain his union membership until June 1, 2019, when he initialed the union-membership application on December 17, 2013? 2. Dkt. Entry 50-9. 3. Agreement Between the State of California and California Statewide Law Enforcement Association (CSLEA) Governing Bargaining Unit 7 (2013-2016), article 3.1A1, Dkt. Entry 50-10, at p. 12. (ii)