WASHINGTON (AP) — The summer that was supposed to mark America’s independence from COVID-19 is instead drawing to a close with the U.S. more firmly under the tyranny of the virus, with deaths per day back up to where they were in March. The delta variant is filling hospitals, sickening alarming numbers of children and driving coronavirus deaths in some places to the highest levels of the entire pandemic. School systems that reopened their classrooms are abruptly switching back to remote learning because of outbreaks. Legal disputes, threats and violence have erupted over mask and vaccine requirements. The U.S. death toll stands at more than 650,000, with one major forecast model projecting it will top 750,000 by Dec. 1.