Peeved. I’m certain that’s exactly how Donald Trump described it to those on Flying Small-Hands Compensation Force One. “You know, this Peña Nieto has peeved me. My dander is definitely on the rise.” Maybe the word “ire” was used.

So Mr. Trump hurriedly inserted a new sentence in his immigration speech, and he soon boomed out from the podium his traditional declaration that the wall would be paid for by Mexico—adding, “They don’t know it yet but they’re going to pay for the wall.”

And so concludes your first example of how Donald Trump would handle sensitive international relations. Next up? That time the Chinese said something about his hair.

What else did Trump say when seeing Peña Nieto’s tweet?

“I have to add back the line that Mexico will pay,” Mr. Trump said, according to the people with him, adding that he couldn’t let that tweet go unanswered.

He couldn’t let the tweet go unanswered. No. Of course he couldn’t.