[jeffersondem]

“No, but the term “at pleasure” comes to us from James Madison's letter to Nicholas Trist where he contrasts “at pleasure” to mutual consent and necessity.”

Could you please post a link to Madison's letter to Trist?

[BroJoeK]

jeffersondem: "Could you please post a link to Madison's letter to Trist?"

Sure, it's here.

FYI, Madison's letter is over 1,700 words in 17 paragraphs, so can't be read in one quick glance.
But it remains the most explicit expression of our Founders' original intentions regarding an alleged unlimited "right of secession".