UNITED STATES CODE TITLE 36 CHAPTER 10 §174. Time and occasions for display
(e) Display on or near administration building of public institutions The flag should be displayed daily on or near the main administration building of every public institution. (
f) Display in or near polling places The flag should be displayed in or near every polling place on election days.
(g) Display in or near schoolhouses The flag should be displayed during school days in or near every schoolhouse.
Hopefully this principal is getting papers served on him right to sue him & the school board for their refusal to fly the American flag on public school property bought & paid for by American taxpayers.