Complex sentence: The court control of the desegregation plan lasted for over a decade, and influenced Boston politics as well as ongoing demographic shifts of Boston's school-age population, which saw a decline of public-school enrollment and white flight to the suburbs.
Split into simpler sentences: The court control of the desegregation plan lasted for over a decade. It influenced Boston politics and contributed to as well as demographic shifts of Boston's school-age population, which saw a decline of public-school enrollment and white flight to the suburbs.