When and why and who decided to change the racism in the southern US states?

Emmet Till -- whistled at a while woman and was brutally murdered.

Rosa Parks -- wouldn't give up her bus seat.

Doctor Martin Luther King -- gave a lot of great speeches and wrote "Letter from Birmingham Jail".

Bull Connor -- with his dogs.

So many others, but Lyndon Johnson was not, NOT, one of them.

All those activists did it, but it was the invention of air conditioning that allowed it.

Before then, the South was simply too hot for the Yankees. They went home.

Aircon also allowed the expansion of the Federal Government. Before that, there was virtually no government at all in Washington in summer.