The Los Angeles Times has documented with Pulitzer quality reporting, the racial gang wars in the L.A. basin. The largest and oldest Latino gang, the Mexican Mafia, has ordered ethnic cleansing of formerly all-black neighborhoods. This has led to an increase in black vs Latino violence. 
Close to my home, the Gateway Harbor area, several blacks have been murdered by Latino gangs in this expressed racial hate crime wave. A six year old black boy was shot in the head and is fighting for his life at Harbor UCLA Medical center — two Latino gang members were arrested for the "random" shooting. Hate crime charges may be filed. 
These hate crimes help explain the growing division in the national Democrat Party. The Democrats since Tammany Hall have always embraced "identity politics". That is, voting for a person because of his skin color and/or his ethnicity. This creates a never ending American balkanization which tears as the fabric of American unity.
So, it should not surprise to Mr. Obama that Latinos were the primary reason for his loss in Texas. Most reports show that Latinos voted for Clinton by a 2/3 ratio. The same ratio was true in California’s primary. Sadly, some reporters pondered why many Latinos reflexively vote against a black person. At the same time, Obama will win Mississippi next week, because more than half the democrats are black. Obama is getting between 83 to 87% of the "black" vote.
This racial polarization is not good for American nor is it good for the Democrats.
The seeds of racial polarization come direct from Democrat Identity Politics. That their caucuses must have "affirmative action" racial percentages. Naturally, this led to literal street fighting between black and Latinos in Texas caucuses, last Tuesday evening.
The animus between Latinos and blacks may endure for years in the Democrat party.
The racial alienation is growing daily between the Clinton and Obama camps. They naturally deny any such phenomena is occurring. Still both carefully measure their individual successes on promoting their racial blocks.
Civil Rights famed Congressman John Lewis recently, tossed his endorsement to Hillary aside and regrouped with Identity politics by switching to Obama. The pressure on Latino and black democrat public figures is striking. We will likely see more defections from each camp based primarily on race. 
This will create huge DEFECTIONS for democrats this fall. Should Obama win the nomination many Latinos will defect. The same is true for Clinton should she win; blacks will stay at home in historic numbers.
This civics lesson ought to teach scholars and Democrat leaders the price to pay for racial polarization is discord, disharmony, and catastrophe to Democrats this fall.