Why Sarah Sanders' 'can't guarantee' answer matters so much

Sanders repeatedly sought to fend off the questions by pointing to Trump's tweet from Monday in which he insisted, "I don't have that word in my vocabulary, and never have. She made it up." (The word, in case you have been living on another planet for the last 48 hours, is the n-word.)

Then NBC's Kristen Welker asked Sanders whether she could guarantee the American public that Trump has never used that particular racial epithet on tape. "I can't guarantee anything, but I can tell you that the President addressed this question directly," Sanders replied.

"I can't guarantee anything."

That's the White House press secretary hedging -- big-time -- on whether or not the President of the United States has used the worst of all racial slurs.

Is Sanders treading carefully because she believes that an "n-word' tape exists? Or simply because she is stung by past experiences in which she told the media one thing only to see the President (or Rudy Giuliani) directly contradict her?

Either way, the end result is the same. Doubt creeps in. A door is opened -- more than a crack. WAY more than a crack when you consider Trump's past history on race -- whether it's his tendency to refer to African-Americans he dislikes as having "low IQs" or his comment that the white supremacist violence in Charlottesville, Virginia came from both sides.

There's already a pretty fat folder of evidence that shows that if Trump isn't a racist, he is more than willing to use the inchoate racism of some of his supporters for political cover and gain.

The Point: Sanders' inability to say -- definitively -- that the President has never used the n-word on tape is startling. Not surprising given what we know about Trump's history on race. But startling nonetheless.

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