"...a half-century ago that was precipitated by the Democratic Party's decision to support the equal rights of African Americans."    -that's historically false. The Democratic Party has attempted to block and impede all efforts to desegregate and integrate African Americans and impart those respective rights to vote-- up to and through "a half century ago."
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AND What's more-- once Democrats accepted the fact that blacks' right to vote and integrate into significant segments of society was a certainty, they shifted their focus to instead implementing as MANY Liberal Socialist policies as they could onto them, this ensuring: A) votes and B) social dependence for decades to come.  Baltimore, Detroit, and Chicago are modern-day casualties of those failed social programs.  A 5-second Google search both confirms this, and articulates the quote LBJ famously gave about implementing social programs to secure the black vote.