NBC News anchor Lester Holt asked a straightforward question.

“Are you going to campaign insult for insult against Donald Trump?” Holt asked presumptive Democratic Party presidential nominee Hillary Rodham Clinton.”

“No,” she answered, “He can run a campaign on insults. We’re going to campaign on the issues.”

What, pretell, are those issues? She said she’s going to keep reminding voters that Trump is “temperamentally unfit to be commander in chief.”

Sigh.

There you have it. Clinton said she’s going to campaign “on the issues,” and then spoke candidly about her presumptive Republican opponent’s temperament.

Is that an “issue”? Yes.

The question now facing the Republican Party brass that is gritting its teeth over whether Trump is capable of keeping his cool is: How is he going to respond?

They fear — with good reason — that Trump is fully capable of flying off the rails. He’s shown that propensity all along the campaign trail so far.

Here’s a scenario that could repeat itself. Longtime observers of Texas politics will remember when this happened.

The year was 1990. Democratic gubernatorial nominee Ann Richards was campaigning against Republican nominee Clayton Williams.

The two of them shared a dais at an event late in the campaign. They each spoke to the crowd. Then as the event drew to a close, Richards walked over to Williams and extended her hand.

Williams refused to shake it. He called Richards a “liar.”

News photographers and TV cameras picked up the snub and reported all over Texas. How did the optics play? Not well … at all!

Williams’s refusal to “shake the hand of a lady” insulted a lot of Texans vicariously.

Richards defeated Williams to become the state’s governor.

Something tells me — if Clinton keeps talking “issues” relating to Trump’s temperamental fitness — that Donald Trump is fully capable of repeating Claytie’s mistake.