The court's newest justice, Neil Gorsuch, will decide if unions have cause for worry.
New research finds that a shift to school-based, peer-led teacher training also can raise student achievement.
State board president, state superintendent say proposed rules on funding for low-income students would intrude on local control and exceed federal authority.
The California Teachers Association campaigned hard for its passage.
They cite innovative work measuring high school readiness and learning mindsets.
Teachers' concerns extend beyond bread-and-butter issues, union leaders say.