What President Trump should be worried about is the reaction from the ideological middle of the country. As the recent NBC/WSJ poll of July 7-9 showed this swing bloc is roughly 20 percent of the overall electorate. If these voters, the vital center of the American electorate, come to believe that Donald Trump as President, his rhetoric and political style, have become a threat to public safety, that is a seminal development.

If that reaction takes hold, El Paso could be for Trump what the Tet offensive was for President Johnson. The moment, as Johnson said, when he lost the country was after he lost Walter Cronkite on the reaction to the Tet offensive. Of course, were Trump to rise to the occasion and succeed at beginning the process of binding the nation’s wounds that, too, would impact public opinion and ameliorate the decline in his public prestige.

Most polls have shown Trump’s job approval ratings dropping — before the tragic events of this weekend — toward 40 percent, though other polls show him at the 45 percent to 46 percent level. But events this sharp move public opinion. So it is too early to truly measure the impact of the process Trump began with the “send them back” attacks.

The real point to be made here is very much beyond narrow politics. This is also way beyond ideology and partisan advantage. In the final analysis, this is about what kind of nation and society America wants to be.