Your answer:

the refusal of many local communities to fully implement the busing plans prepared specifically for them by federal district court judges, who have no effective means of forcing them to comply.

the Supreme Court ruling that limits the use of busing across school district boundaries, which has insulated predominantly white suburban schools from busing plans.

state laws that have prohibited busing in any of the state’s school districts.

local referenda on busing, which have produced the two-thirds vote against busing that is required to rescind the policy.

school superintendents who routinely violate federal law.