What caused a "shift in public opinion"

In the three weeks since George Floyd’s death, public opinion on race and policing has zoomed left. Support for Black Lives Matter is skyrocketing. Almost 60 percent of Americans think police are more likely to use excessive force on an African American suspect than a white suspect — a sea change from 2016, when only 34 percent of registered voters said the same. And an overwhelming majority of Americans now say they support a wide variety of police reforms, even if polling suggests that “defend the police” is still a radioactive slogan.

Explanation: Credits: The Washington Post; Public opinion on policing has shifted.

the  seven  days  battles  were  a series of seven battles over seven  days from june 25 to july 1, 1862, near richmond, virginia,  during  the american civil war. the  seven  days ended with mcclellan's army in relative safety next to the james river, having suffered almost 16,000 casualtiesduring  the retreat.